Mares Spa GENIUS Dive Computer User Manual
Mares Spa Dive Computer
user manual

Instruction Manual
Color Dive Computer

GENIUS Dive Computer
2
• TABLE OF CONTENTS
IMPORTANT WARNINGS  3
DISCLAIMER 3
PART I   4
• 1.  INTRODUCTION  4
1.1. GLOSSARY  4
1.2.  OPERATING MODES  5
1.3.  TURNING ON GENIUS AND MAIN MENU  5
1.4.  RECHARGEABLE BATTERY   5
1.4.1.  CHARGING THE BATTERY  5
1.5.  COMMUNICATING VIA USB CABLE OR BLUETOOTH  5
1.6.  BUTTON OPERATION  6
1.7.  IN CASE OF EMERGENCY ICE  6
1.8.  MOUNTING AND PAIRING OF THE TANK MODULE OPTIONAL  6
1.9.  TURNING OFF GENIUS 7
• 2.  SET DIVE  7
2.1. MODE  7
2.2. ALGORITHM  7
2.2.1.  MAIN GF  7
2.2.2.  ALTERNATE GF TO BE INTRODUCED VIA FREE FIRMWARE 
UPGRADE SOON  7
2.2.3. PERSONALIZATION  7
2.2.4.  REPETITIVE DIVES  8
2.2.5. MULTIDAY  8
2.3.  GAS INTEGRATION  8
2.3.1.  COLOR CODING FOR PRESSURE RANGES  8
2.4. WARNINGS  8
2.4.1.  MAX DEPTH  8
2.4.2.  DIVE TIME  8
2.4.3.  NO STOP  9
2.4.4.  ENTERING DECO  9
2.4.5. RGT  9
2.5. MULTIGAS  9
2.5.1. PREDICTIVE  9
2.5.2.  ALLOW SWITCH BELOW MOD  9
2.6.  FUTURE DECO  9
2.7. WATER  9
2.8.  NIGHT MODE  9
2.9.  DEEP STOP  9
2.10.  DECO STOP  9
2.11. SECONDS  9
2.12.  LINKED MAP  9
2.13.  ERASE DESATURATION  9
2.14.  ALL SILENT MODE  9
2.15.  ASCENT VIOLATION   9
• 3.  SET COMPUTER  9
3.1. LANGUAGE  9
3.2. UNITS  10
3.3. CLOCK  10
3.4. BRIGHTNESS  10
3.5.  COMPASS DECLINATION  10
3.6.  COMPASS CALIBRATION  10
• 4.  DIGITAL COMPASS  10
4.1.  SETTING A BEARING  10
• 5.  INFO  10
• 6.  MAPS AND PHOTOS  10
• 7.  BUTTON LOCK  10
PART II   10
• 8.  DIVING WITH GENIUS  10
8.1.  A FEW WORDS ABOUT NITROX   10
8.2. ALTITUDE  11
8.3. LOGBOOK  11
8.4.  DIVE PLANNER  11
8.5. ALARMS  11
8.5.1.  ASCENT RATE   11
8.5.2. MOD/ppO2 11
8.5.3.  CNS = 75%  11
8.5.4.  MISSED DECOMPRESSION STOP  12
8.5.4.1.  MISSED DECO STOP MODE  12
8.5.5.  LOW TANK PRESSURE / RGT < 3 MIN  12
8.5.6.  LOW BATTERY  12
• 9.  DISPLAY INFORMATION  12
9.1.  DETAILED DESCRIPTION OF DISPLAYED DATA  13
9.2.  DEEP, DECO AND SAFETY STOPS  13
9.3.  FUTURE DECOMPRESSION  13
9.4.  DIVE PROFILE   14
9.5.  COMPASS   14
9.6.  TISSUE SATURATION GRAPH  14
9.7.  DECO SUMMARY TABLE  14
9.8.  VIEWING MAPS DURING A DIVE  14
9.9.  UNDERWATER MENU  14
• 10.  AFTER THE DIVE  15
• 11.  DIVING WITH MORE THAN ONE GAS MIXTURE  15
11.1.  SETTING MORE THAN ONE GAS   15
11.2.  SWITCHING GAS  15
11.3.  SPECIAL SITUATIONS  16
11.3.1.  SWITCHING BACK TO A GAS MIXTURE WITH LOWER 
OXYGEN CONCENTRATION  16
11.3.2.  SUBMERGING BELOW THE MOD AFTER A GAS SWITCH   16
11.3.3.  RGT WHEN DIVING WITH MORE THAN ONE GAS MIXTURE  16
11.3.4.  LOGBOOK FOR DIVES WITH MORE THAN ONE GAS MIXTURE  16
11.4.  DIVING WITH MORE THAN ONE GAS MIXTURE  TRIMIX OR HELIOX  16
• 12.  BOTTOM TIMER MODE  16
12.1.  DIVE VIOLATION INDUCED BOTTOM TIMER MODE  16
• 13.  TAKING CARE OF GENIUS  16
13.1.  TECHNICAL INFORMATION  16
13.2. MAINTENANCE  17
13.2.1.  REPLACING THE BATTERY IN GENIUS 17
• 14.  WARRANTY  17
14.1.  WARRANTY EXCLUSIONS  17
14.2.  HOW TO FIND THE PRODUCT SERIAL NUMBER AND ELECTRONIC ID  18
• 15.  DISPOSAL OF THE DEVICE  18

3
No part of this document may be reproduced, 
stored in a retrieval system, or transmitted 
in any form without the written permission of 
Mares S.p.A.
Mares adopts a policy of continuing 
improvement, and therefore reserves the right 
to make changes and enhancements to any of 
the products described in this manual without 
notice.
Under no circumstances shall Mares be held 
responsible for any loss or damage sustained 
by third parties deriving from the use of this 
instrument.
 WARNING
A dive computer is an electronic 
instrument and as such it is not immune 
to failure. To protect yourself against the 
unlikely event of a failure, in addition to the 
dive computer, also use a depth gauge, a 
submersible pressure gauge, a timer or 
watch, and dive tables. 
 WARNING
Do not dive if the display appears unusual 
or unclear.
 WARNING
The dive computer must not be used in 
conditions that preclude its use (e.g.: low 
or no visibility, making it impossible to 
read the gauge).
 WARNING
The dive computer cannot ensure against 
possible decompression sickness.
DISCLAIMER
This manual describes how to operate an 
instrument and it describes the information 
provided by the instrument during a dive.
Neither this manual nor the instrument are a 
substitute for dive training, common sense and 
good diving practices.
How the information provided by the 
instrument is interpreted and put to use by 
the diver is not the responsibility of Mares. 
Read the manual carefully and make sure you 
understand completely how the instrument 
works and the information it provides during 
a dive, including information on depth, time, 
decompression obligations and all warnings 
and alarms. Unless you fully understand how 
the instrument works and the information 
it displays and unless you accept full 
responsibility for using this instrument, do not 
dive with it.
• IMPORTANT WARNINGS

GENIUS Dive Computer
4
• PART I 
• 1.  INTRODUCTION
1.1.  GLOSSARY
AGF:  Alternate gradient factor
AIR: Air dive
ASC: Total ascent time, the time it takes to perform the ascent from your current depth to the surface in a decompression dive, 
including all decompression stops and assuming an ascent rate of 10m/min or 33ft/min.
ASC + X: The overall ascent time inclusive of all decompression stops if the dive is extended by X minutes at the current depth.
AVG: Average depth, calculated from the beginning of the dive.
CNS: Central Nervous System. CNS% is used to quantify toxic effects of oxygen. 
DESAT: Desaturation time. The time needed for the body to eliminate the nitrogen taken up during diving.
D-TIME: Dive time, the whole time spent below a depth of 1.2m/4ft.
Gas integration: The feature in Genius to include tank pressure information in its calculations and to display it on the computer screen.
Gas switching: The act of changing from one breathing gas to another.
GF:  Gradient factor
Gradient Factor: Percentage of Bühlmann’s original value of maximum allowed supersaturation 
Heliox: A breathing gas containing Oxygen and Helium.
Max depth: Maximum depth attained during the dive. 
MOD: Maximum Operating Depth. This is the depth at which the partial pressure of oxygen (ppO2) reaches the maximum allowed 
level (ppO2max). Diving deeper than the MOD will expose the diver to unsafe ppO2 levels. 
Multigas: Refers to a dive in which more than one breathing gas is used (air and/or Nitrox).
Nitrox: A breathing mix made of oxygen and nitrogen, with the oxygen concentration being 22% or higher. 
NO-FLY: Minimum amount of time the diver should wait before taking a plane.
No deco time: This is the time that you can stay at the current depth and still make a direct ascent to the surface without having to perform 
mandatory decompression stops.
O2:Oxygen.
O2%: Oxygen concentration used by the computer in all calculations.
Pairing: The act of establishing a coded RF communication between Genius and a dedicated device, such as a tank module. 
ppO2:Partial pressure of oxygen. This is the pressure of the oxygen in the breathing mix. It is a function of depth and oxygen 
concentration. A ppO2 higher than 1.6bar is considered dangerous.
ppO2max: The maximum allowed value for ppO2. Together with the oxygen concentration it defines the MOD.
Switch depth: The depth at which the diver plans to switch to a higher oxygen concentration mix while using the multigas option.
Trimix: A breathing gas containing Oxygen, Nitrogen and Helium.
TTR: Time To Reserve, it is the time that a diver can spend at the current depth before reaching the tank reserve.
SURF INT: Surface interval, the time that has elapsed since the end of the dive.
RGT: Remaining Gas Time, it is the time that a diver can spend at the current depth before having to ascend in order to reach the 
surface with the tank reserve still available.

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1.2.  OPERATING MODES
The functions of the Genius computer can 
be grouped into three categories, each 
corresponding to a specific mode of operation:
• surface mode: the computer is dry on 
the surface. In this mode you can change 
settings, review your logbook, use the dive 
planner, see remaining desaturation after a 
dive, download to PC and much more;
• dive mode: the computer is at a depth of 
1.2m/4ft or more. In this mode, Genius 
monitors depth, time, temperature and 
performs all decompression calculations; 
dive mode itself can be broken down into 4 
sub categories: 
- pre-dive (Genius is on the surface but 
actively monitoring ambient pressure, so 
that it can begin to calculate a dive the 
instant it is submerged below 1.2m/4ft);
- dive
- surfacing (Genius is on the surface at 
the end of a dive; dive time calculation 
is halted but if the diver submerges 
within threeminutes the dive is resumed 
including the time spent on the surface; 
this for instance would allow a diver to 
surface momentarily to set a bearing 
towards the boat, then submerge again 
and swim towards the boat);
- post-dive (after the threeminutes of 
surfacing mode, Genius closes the 
logbook and reverts to a display showing 
desaturation time, no-fly time and surface 
interval; this lasts until the desaturation 
and the no-fly time both have been 
reduced to zero);
• sleep mode: the computer is on the 
surface after 3 minutes without operation 
(10minutes from pre-dive mode). Though 
the computer appears to be turned 
off completely, it is still active. Genius 
computes tissue desaturation and checks 
the ambient pressure once every 20 
seconds for uninterrupted monitoring of the 
environment. 
1.3.  TURNING ON GENIUS AND 
MAIN MENU
To start the computer, press the left button. 
This brings up the home display, shown in 
Figure 1. The home display provides at-a-
glance information about time, temperature, 
battery status, settings of the algorithm and, 
when paired to an active transmitter, tank 
pressure. From the home display you can call 
up the main menu with all available settings 
and functions, but you can also directly reach 
certain useful functions such as logbook, dive 
planner, gas and algorithm settings, bluetooth 
connection.
Once in the main menu, you will see the 
familiar look of an icon-based user interface. 
From the top left, in sequence, there are:
SET DIVE: here you can review and set 
all parameters relating to a dive;
SET COMPUTER: set the language, the 
clock, display brightness and more;
COMPASS: from within this menu you 
can use the compass while on the 
surface, for instance to set a bearing 
which you will call up later on in the 
dive to navigate towards a wreck;
INFO: find information about the 
hardware and firmware of your Genius;
MAPS: view all maps uploaded to your 
Genius;
PHOTOS: view all images uploaded to 
your Genius;
BLUETOOTH: establish a bluetooth 
connection to a device such as a 
smartphone;
BUTTON LOCK: lock the buttons so 
that the battery is not accidentally 
drained during travel.
1.4.  RECHARGEABLE BATTERY 
Genius uses a lithium-ion rechargeable 
battery. A full charge allows you up to 40 hours 
of diving, depending on the usage of the high 
intensity on the backlight and the temperature 
of the water. The display alerts you of the 
status of the battery. The four possible 
situations are described as follows: 
-  A solid green battery symbol means Genius 
has between 70 and 100% charge;
-  A partially filled green battery symbol 
means Genius has between 40 and 70% 
charge, still enough for safe diving;
-  A partially filled yellow battery symbol 
means Genius has between 20 and 40% 
charge. 
-  A partially filled red battery symbol means 
Genius has between 0 and 20% charge. This 
is not sufficient to ensure a safe dive hence 
the computer is disabled from functioning. 
In the event that the charge drops below 20% 
during a dive, the message LOW BATTERY 
appears on the display. When you see this 
message, you should consider starting a safe 
ascent as there may not be enough charge to 
continue diving.
 WARNING
-  Starting a dive with less than 20% charge 
can cause the computer to fail during the 
dive. Recharge the battery as soon as 
you notice this message. 
-  In sleep mode Genius uses up the 
battery at a a very slow rate. If you 
haven’t used Genius in several weeks 
there may be a noticeable drop in battery 
level, so you may have to recharge it 
before diving.
- Leaving Genius unattended for long 
periods of time such that the battery will 
be completely discharged does not harm 
neither the battery nor Genius. Logbook 
data and all settings will be saved. After 
charging you must however set the time 
and date again.
-  When the battery in Genius is completely 
discharged, it may take up to 20 minutes 
from the moment it is connected to a 
power source before Genius reacts.
-  Temperature can noticeably affect 
battery performance. A low battery 
warning may appear when diving in cold 
waters even if you think that the battery 
should have sufficient charge.
-  It is advised that you charge the battery if 
you intend to dive in cold water.
The rechargeable battery has a life time of 
approximately 500 charging cycles. Please 
contact your authorized Mares dealer if you 
need to replace it.
1.4.1.  CHARGING THE BATTERY
The battery takes about 4 hours to charge 
from completely empty to completely full 
when using the adapter that came with the 
computer. It can take up to 8 hours when using 
a standard adapter as not all adapters feed the 
same current to the USB port. To charge the 
battery, use the special clip and the USB cable, 
connecting it either directly to a power supply 
or to the USB port of a PC.
1.5.  COMMUNICATING VIA USB 
CABLE OR BLUETOOTH
Genius can communicate via low power 
bluetooth directly to a smartphone, a PC or 
a Mac. The data transfer is such that only 
logbook information can be transferred via 
bluetooth while firmware upgrades and image 
or map uploads have to be carried out via PC 
or Mac.
To connect Genius to a PC or Macintosh 
computer, use the dedicated clip and the USB 
cable. Once connected, Genius will show the 
USB symbol on the display.
To initiate a bluetooth connection, press and 
hold the BT button from the home display or 
select the   icon from the main menu, then 
start the MySSI app on your smartphone and 
follow the instructions.

GENIUS Dive Computer
6
1.6.  BUTTON OPERATION
Genius has four buttons. These buttons allow 
you to access menus and change settings 
while in surface mode. During the dive they 
switch displays, call up the compass or the 
map function, and allow to display further 
information on the computer screen. The 
function of each button is identified by a set of 
letters or an icon placed just above the button 
itself. In certain circumstances, for instance 
when erasing a set bearing in the digital 
compass or when calling up the gas switch 
function during a multigas dive, a button can 
perform two tasks, depending on whether it is 
pressed and released or pressed and held for 
one second.
In such case, there will be two groups of 
letters or icons above a button: the left one 
corresponds to the press-and-release action, 
the right one to the press-and-hold action.
From the home display you have the following 
possible operations (press/press and hold) for 
the buttons from left to right (Fig. 1):
-  PRE/POST: enters PRE dive mode/enters 
POST DIVE mode (only if there is remaining 
desaturation in the computed tissues);
-  LOG/PLAN: enters the logbook/enters dive 
planner mode;
-  GAS/GF: enters oxygen and helium setting 
menu/displays gradient factor settings table;
-  MENU/BT: goes to main menu/starts 
bluetooth connection.
During a dive, icons are used to define the 
button function. From left to right you will see 
(Fig. 2):
/ : enter compass mode/enter 
underwater menu
/ : switch to graphic display/call up 
list of stops
/ : change field in lower right 
corner/initiate gas switch
/ : change field in top right corner/
call up tissue saturation graph.
The dive display is described in more detail in 
section 9
Other icons that might appear during a dive are:
AGF: allows you to switch between the main 
set of GF and the alternate set
:calls up deco summary table.
:allows to set a bearing (press) or 
erase a set bearing (press and hold) 
(COMPASS)
:makes stopwatch appear (COMPASS)
:makes stopwatch disappear 
(COMPASS)
:restarts stopwatch (COMPASS and 
DIVE, only if stopwatch on screen)
:exit from predive mode
:return to standard display (COMPASS, 
TISSUE GRAPH, MAP, GAS TABLE).
1.7.  IN CASE OF EMERGENCY 
ICE
Genius allows you to enter information about 
yourself, such as name, contact information, 
emergency number, insurance policies and 
allergies. This information is entered via the 
PC software Dive Organizer. Alternatively, it 
can also be entered via the Divers’ Diary Mac 
software. The first two lines of the ICE are 
displayed in the home display.
1.8.  MOUNTING AND PAIRING 
OF THE TANK MODULE 
OPTIONAL
Genius features an exclusive two-way 
communication technology through which it 
can communicate with up to 5 tank modules 
regarding tank pressure and gas consumption 
information via patented interference-free 
communication. Each tank module needs to 
be mounted on a high pressure port of a first 
stage regulator.
In order for Genius to display tank pressure 
and gas consumption information, you must 
first establish a channel of communication 
between the tank module and Genius. This 
is called pairing. This operation needs to be 
performed only once and ensures a permanent 
and interference-free link between the two 
devices.
NOTE
To perform the pairing operation, the tank 
module must be pressurized to at least 
15bar/220psi. Hence it must be mounted 
on a first stage regulator, which is itself 
mounted on a full scuba tank and the valve 
opened.
To mount the tank module on the first stage 
regulator, first remove the high pressure port 
plug, then screw in the tank module gently by 
hand until you feel a minimum of resistance, 
then use a 19mm wrench to tighten it (Fig. 3). 
NOTE
-  Do not force the tank module while 
holding it by the plastic cap. 
-  Do not overtorque while using the 
wrench: the o-ring seal is assured as 
soon as you feel the first resistance. The 
only reason for using a wrench to tighten 
a bit more is to prevent the tank module 
from unscrewing itself over time.
The Mares tank module communicates 
via radio frequency with Genius. For best 
transmission, we recommend positioning the 
tank module as described in Figure 4.
To pair the tank module with the Genius, 
proceed as follows:
-  Open the tank valve to pressurize the tank 
module. You now have two minutes to 
perform all steps listed below;
-  Go into SET DIVE/GAS INTEGRATION/PAIR 
DEVICES
-  Choose the channel that you wish to assign 
to the device (if this is your only tank module 
for single gas diving, choose G1. G2 through 
G5 are used for multigas dives. More 
information on this in section 11);
- Place Genius at about 15 cm / 6 inches from 
the tank module as shown in Figure 5.
- Push SELECT and wait until the progress 
bar advances to the end. You will either 
see the message PAIRING SUCCESSFUL 
or PAIRING NOT SUCCESSFUL. In the first 
case you have successfully established 
a connection, in the second you need to 
repeat the operation, but you must turn off 
the valve and depressurize the first stage 
completely, then wait 1 minute before 
attempting again.
NOTE
-  When diving with more than one gas 
mixture, tanks G1 through G5 must be 
set to increasing oxygen levels. Refer 
to section 11 for more information on 
multigas diving.
-  A tank module can only be paired to one 
channel on one Genius. If you pair the 
same tank module to a second channel 
on the same Genius or to a second 
Genius, the first one will be erased. 
After a successful pairing of G1 to Genius, 
the home and the pre-dive display will show 
the tank pressure in either bar or psi. If tank 
G1 has not been paired, Genius will show an 
empty field instead of a pressure value. If G1 
has been paired but Genius is not receiving any 
signal, it will show - - - instead of a pressure 
value. 
NOTE
-  The Mares tank module has a range of 
approximately 1.5m/5ft.
-  If a tank module battery is weak, Genius 
alerts you with a screen message 
referencing the channel designation 
assigned to the tank module in question.
-  During a dive, you can ask Genius to 
display the battery status of the tank 
module. More information about this in 
section 8.5.6 and 9.
Refer to the dedicated tank module manual for 
information on how to replace the battery in 
the tank module.
NOTE
-  You do NOT need to repeat the pairing 
procedure after a battery replacement in 
the tank module.
-  You do NOT need to repeat the pairing 
procedure if the battery in Genius is 
completely empty.
-  You do NOT need to repeat the pairing 
procedure after upgrading the firmware 
in your Genius.
1.9.  TURNING OFF GENIUS
Genius turns off automatically after 3 minutes 
without operation when in surface mode and 
after 10minutes without operation when in 
pre-dive mode. From the main menu, you 
can also turn it off manually by selecting the 
BUTTON LOCK icon. 

7
• 2.  SET DIVE
MENU Description
SET DIVE
MODE
Allows you to choose 
between air, nitrox, trimix and 
bottom timer mode. 
ALGORITHM
Allows you to set main and 
alternate gradient factors, 
personalization levels, and 
more.
GAS 
INTEGRATION
Allows you to synchronize 
your Genius with optional 
tank modules and to define 
all parameters concerning 
gas integration (tank volume, 
operating tank pressure, tank 
reserve and more).
WARNINGS
Allows you to define and 
activate certain warnings 
individually
MULTIGAS
Allows you to define 
parameters relating to 
multigas dives.
FUTURE 
DECO
Allows you to set the 
parameters for the future 
deco prediction. Please refer 
to section 2.6 for more details 
on this.
WATER Allows you to choose 
between salt and fresh water.
NIGHT MODE
Allows you to choose the night 
mode display (white numbers 
on black background) as 
default display.
DEEP STOP
Allows you to activate or 
deactivate the visualization of 
deep stops.
DECO STOP
Allows you to choose the 
depth of the shallowest stop 
among 3m/10ft, 4.5m/15ft, 
6m/20ft.
SECONDS Allows you to show the dive 
time in minutes and seconds.
LINKED MAP
Allows you to select a map 
which you can call up on the 
display during the dive.
ERASE 
DESAT
Allows you to reset the 
inert gas saturation to zero, 
thereby erasing the effects of 
a previous dive. This is only for 
people who plan to lend their 
computer to another diver 
who has not performed a dive 
within the last 24 hours.
ALL SILENT 
MODE
Allows you to silence the dive 
computer.
ASCENT 
VIOLATION
Allows you to turn off the dive 
violation due to uncontrolled 
ascent. This is for dive 
instructors only, who may 
find themselves in such a 
situation because of their 
teaching requirements.
2.1.  MODE
In this menu you define the type of gas you 
will be breathing during the dive (AIR as 
SINGLE GAS, NITROX as SINGLE GAS, NITROX 
as MULTIGAS, TRIMIX as MULTIGAS). You 
can also set Genius to BOTTOM TIMER, in 
which case Genius will show only time, depth 
and temperature: it will not carry out any 
decompression calculation and it will not show 
any warnings and alarms. 
Use   and   to highlight your choice, 
then press SELECT to activate it. AIR is the 
equivalent of setting NITROX to 21% and a 
ppO2max of 1.4bar. 
When selecting NITROX, you are taken to 
a submenu in which you can define the 
percentage of oxygen in the mixture (O2%) and 
the maximum value of oxygen partial pressure 
(ppO2max) for up to three breathing mixes. The 
maximum possible value for the ppO2max is 
1.6bar. Most training agencies recommend not 
to exceed a value of 1.4bar.
Once inside this menu, use   and   to change 
the O2%, and watch how this affects the 
maximum operating depth (MOD). Then press 
NEXT to move on to the ppO2max and use   
and   to change the value, again noticing 
how this affects the MOD. Press SET to save 
and exit the menu. Note that you can press 
BACK after having set the O2% to save and exit 
skipping the ppO2max setting.
 WARNING
-  Diving with Nitrox may only be 
attempted by experienced divers after 
proper training from an internationally 
recognized agency.
-  Before every dive and after changing 
the tank, you must make sure that the 
set oxygen concentration in Genius 
corresponds to the oxygen concentration 
in the tank. Setting the wrong oxygen 
concentration can lead to serious injury 
or death.
This is also the menu where you would be 
setting your decompression gases if you dived 
with more than one gas. See chapter 11 for 
more information about diving with more than 
one gas or for dives with trimix.
2.2.  ALGORITHM
Genius employs the unmodified Bühlmann 
ZH-L16C algorithm with gradient factors. 
Gradient factors are used to lower the 
maximum tolerated supersaturation in the 
tissues with respect to Bühlmann’s original 
values. This results in less nitrogen in the body 
at the end of the dive, which under normal 
circumstances makes the dive safer. Gradient 
factors are expressed in pairs: the first value, 
also called GF low, represents the percentage 
of the original Bühlmann value that defines the 
beginning of the final ascent (relevant only in 
decompression dives); the second value, also 
called GF high, represents the percentage of 
the original Bühlmann value that defines the 
residual nitrogen at the surface at the end of 
a dive. As an example GF 50/85 will get you 
to the surface with a 15% additional margin 
with respect to Bühlmann’s original maximum 
tolerated supersaturation and, if this was a 
decompression dive, your first decompression 
stop would have been at a depth such that you 
would not have exceeded 50% of Bühlmann’s 
original value at that depth. 
For more information about 
gradient factors, please refer to 
www.mares.com/sports/diving/gradientfactor
From the home display, press and hold the 
third button from the left (GF) to display a table 
listing all settings (Fig. 6).
2.2.1.  MAIN GF
This is where you set the conservatism level 
of the ZH-L16C algorithm via gradient factors. 
We use Bühlmann’s original values reduced by 
15% as a starting point, and you can make the 
algorithm more conservative from there. There 
are four predefined sets of gradient factors 
with increasing conservatism from R0 (85/85) 
to R3 (50/60) for recreational dives and from 
T0 (30/85) to T3 (25/40) for tech dives. You 
can also enter the GF low and GF high values 
directly via the CUSTOM setting. The default 
value is R0 (85/85).
2.2.2.  ALTERNATE GF TO BE INTRODUCED 
VIA FREE FIRMWARE UPGRADE 
SOON
Genius allows you to define an alternate set 
of gradient factors, to use when you need 
to cut your decompression short in case of 
an emergency. The set of alternate gradient 
factors cannot be more conservative (i.e. 
lower) than the main set of GF values. The 
default value is R0 (85/85).

GENIUS Dive Computer
8
2.2.3.  PERSONALIZATION
This menu allows you to define additional 
conservatism in a way similar to going from 
R0 to R1, R2 or R3 but in a more personal way. 
It comprises two submenus, labelled MAIN 
and ALTERNATE, each of which has three 
submenus, called PHYSIO, DIVE, I TODAY. The 
values set in each menu are subtracted from 
the respective MAIN GF and ALTERNATE GF 
value yielding the values used by Genius for 
the decompression calculations.
PHYSIO allows you to define an additional 
conservatism based on how you feel about 
yourself and diving overall. Each step from 
LOW to MEDIUM to HIGH incrementally 
reduces both gradient factor values by 10. 
There is also a setting called ADVANCED, 
which increases the gradient factor by 5 so 
that a maximum of 90/90 can be achieved. 
This is only for experienced divers who have 
accumulated enough experience to know they 
can tolerate such levels of inert gas. We do not 
recommend doing this since it increases the 
risk of decompression sickness thus Genius 
requires that you insert a code (1234) to allow 
the setting. 
The value set in PHYSIO remains stored until 
you manually change it. The default value is 
OFF.
DIVE allows you to define an additional 
conservatism based on how you feel about 
the dive conditions. Each step from LOW to 
MEDIUM to HIGH incrementally reduces both 
gradient factor values by 3. If you think there 
will be much current or the water will be 
very cold, pick one of these settings. Since 
conditions can actually be different from what 
you expected, this parameter can be edited 
also DURING the dive (via the underwater 
menu). The default value is OFF.
The value set in DIVE resets automatically to 
OFF at midnight. 
I TODAY allows you to define an additional 
conservatism based on how you feel about 
yourself today, for instance to account for 
a restless night or not having hydrated 
sufficiently. Each step from LOW to MEDIUM 
to HIGH incrementally reduces both gradient 
factor values by 5. 
The default value is OFF. Also the value set 
in I TODAY resets automatically to OFF at 
midnight. 
2.2.4.  REPETITIVE DIVES
The original Bühlmann algorithm assumes 
normal offgassing of inert gas via diffusion 
after a dive. This seems to work well for 
most people and indeed most dive computers 
available today compute repetitive dives like 
this. There is evidence however that some 
people produce bubbles after a dive, or 
produce more bubbles than others, and these 
bubbles though harmless slow down the 
offgassing process. Surface intervals of three 
hours or longer are known to dissipate most if 
not all bubbles. Genius allows you to account 
for this by applying an additional conservatism 
to repetitive dives, reducing both gradient 
factor values by 8 upon surfacing from a dive 
and then increasing it again by 1 every 15 
minutes of surface interval. When setting REP 
DIVE to ON you will have recovered the full 
gradient factor values after a two-hour surface 
interval. Any dive started before such surface 
interval will carry an automatic additional 
gradient factor reduction. If you set the value 
to OFF, the GF values are not modified during 
a surface interval.
The setting can be applied independently to 
the MAIN GF and ALTERNATE GF values. The 
default values are OFF for MAIN GF and OFF 
for ALTERNATE GF.
2.2.5.  MULTIDAY
Increasing inert gas load on your tissues over 
several days of diving has effects that are not 
fully understood and are different from person 
to person. Most dive computers available today 
do not account for this and compute simple 
inert gas offgassing by diffusion. Genius allows 
you to increase the conservatism automatically 
for each day of diving with less than 24-hours 
of surface interval by reducing both gradient 
factor values by 2 on the second day, an 
additional 2 on the third day and an additional 
2 on the fourth day up to a maximum of 6. 
Default values are OFF for MAIN GF and OFF 
for ALTERNATE GF.
2.3.  GAS INTEGRATION
This menu contains seven submenus. The first 
one allows you to pair the tank modules to 
the Genius. Please refer to section 1.8 for the 
description of the pairing process. 
The second menu, GAS SUPPLY ESTIMATE 
allows you to choose between two concepts of 
available gas supply estimate:
-  TTR (time to reserve) is the time, in minutes, 
before you will reach the tank reserve at the 
current depth and at the current breathing 
rate;
-  RGT (remaining gas time) is the time you 
can still spend at the depth you are at, based 
on the current gas consumption, before you 
must initiate an ascent in order to arrive at 
the surface without going below the tank 
reserve. This calculation accounts for all 
existing and upcoming decompression 
obligations.
When using TTR, you have a clear idea of when 
you will reach the tank reserve, but you must 
use it carefully to gauge when to initiate the 
ascent in order to arrive at the surface with 
the tank reserve. This is a good method when 
you don’t have decompression obligations, but 
is less powerful when doing decompression 
dives.
The RGT is very useful when doing 
decompression dives since it accounts for 
additional decompression incurred during the 
RGT itself.
The third menu, TANK VOLUME, allows you 
to set the size of the volume of the tank, 
individually for G1 through G5. This parameter 
is important for a correct evaluation of your 
gas consumption in l/min or cu ft /min. Default 
setting is 12l for metric system and 80 cubic 
feet in imperial. For the imperial setting it 
is paramount that you also set the correct 
operating tank pressure, since the size of the 
tank is referenced to this pressure.
The fourth menu, OPERATING TANK 
PRESSURE, is where you define the nominal 
fill pressure of your tanks. This can be set 
individually for each tank (G1 through G5). 
This value is used to scale the graphic tank 
representation but also to define the pressure 
ranges for color coding (described in section 
2.3.1). When the units are set to ft/°F/psi, 
this value is important because together with 
the tank volume it allows Genius to correctly 
evaluate your gas consumption in cu ft/min. 
Default values are 200bar and 3000psi.
The fifth menu, MID TANK WARNING, is the 
value at which Genius triggers a half tank 
warning. This can be set individually for each 
tank (G1 through G5). This value is also used in 
the definition of the pressure ranges for color 
coding as described below. Default values are 
100bar and 1500 psi.
The sixth menu, TANK RESERVE, is the 
value at which an alarm is triggered because 
you should always be at the surface before 
reaching this level. Furthermore, this value 
is used to calculate the TTR and RGT values 
(see section 8.5.5 and 9.1). This can be set 
individually for each tank (G1 through G5). 
Default values are 50bar and 750psi. 
The seventh and last menu is called 
AUTOZERO RESET and it allows you to set the 
ambient pressure reading on the tank module 
in the unlikely event of a drift of the zero value. 
You would perform this operation if you noticed 
a significant difference between the read-out 
of Genius and a calibrated pressure gauge also 
connected to the same first stage.
Due to the potential of introducing an error in 
the tank module measurement, please contact 
your Mares Authorized Service Center before 
performing this operation.
2.3.1.  COLOR CODING FOR PRESSURE 
RANGES
In addition to a numeric value for the tank 
pressure, Genius uses color coding for 
an immediate at-a-glance tank pressure 
visualization. The color is applied to the inside 
of the tank pictogram. The pressure range 
from operating tank pressure to empty tank 
is split into 4 ranges, from BLUE to GREEN to 
YELLOW to RED. The ranges are so defined:
BLUE: the upper half between OPERATING 
TANK PRESSURE and MID TANK WARNING
GREEN: lower half between OPERATING TANK 
PRESSURE and MID TANK WARNING
YELLOW: between MID TANK WARNING and 
50bar/750psi.
RED: below 50bar / 750psi

9
2.4.  WARNINGS
2.4.1.  MAX DEPTH
Genius allows you to set an alarm at a depth 
independent of the MOD. The default value is 
OFF. Using the   and   buttons you can set 
it between 10m / 30ft and up to just shy of the 
MOD, in 1m / 5ft increments. Upon reaching the 
depth defined in this alarm, the message MAX 
DEPTH REACHED appears on the screen and 
stays there until you ascend above the set limit.
2.4.2.  DIVE TIME
Genius allows you to set a time alarm, 
triggering also a warning at half of the set time 
limit. The default value is OFF. Using the   
and   buttons, you can set the value between 
20 and 90 minutes in 2-minute increments. 
Upon reaching half of the set limit, the 
message TURN AROUND appears and stays 
on the display until you hit any button to 
acknowledge it. Upon reaching the set time 
limit, the message TIME LIMIT appears and 
stays on the display until you hit any button to 
acknowledge it.
2.4.3.  NO STOP
When this is set to ON, a warning will alert you 
when the NO STOP time reaches 2 minutes.
2.4.4.  ENTERING DECO
When this is set to ON, a warning will alert you 
when a mandatory decompression stop has 
been calculated by Genius.
2.4.5.  RGT
In multigas dives, when this is set to ON, a 
warning will alert you when the RGT reaches 3 
minutes. For single gas dives this is an ALARM 
and is always ON.
2.5.  MULTIGAS
2.5.1.  PREDICTIVE
When set to ON, Genius will consider all 
gases in the decompression calculation, 
with switches carried out at the MOD of each 
gas. When set to OFF, the decompression 
calculation will consider the currently 
breathed gas only. See Section 11 for more 
information about the PREDICTIVE feature.
The default value is ON.
2.5.2.  ALLOW SWITCH BELOW MOD
When set to ON, Genius will allow a switch to a 
gas at a depth deeper than the MOD of the gas 
(resulting in an immediate MOD alarm). 
The default value is ON.
2.6.  FUTURE DECO
In this menu you can define the parameters of 
the future deco prediction and of the runaway 
deco alarm. Refer to section 9.3 for more 
information.
2.7.  WATER
You can set the computer to fresh water, salt 
water or EN13319 calibration, depending 
on where you intend to dive. Setting the 
wrong water type entails an error in depth 
measurement of maximum 3% (i.e. at a 
depth of 30m/100ft, a computer set to salt 
water will show 29m/97ft in fresh water 
whereas a computer set to fresh water will 
show 31m/103ft in salt water). Note that this 
does not affect the proper functioning of the 
computer, since the computer performs all 
of the calculations based purely on pressure 
measurements. EN13319 corresponds to a 
water density of 1.0197kg/l and it is used in 
European Norm 13319. 
2.8.  NIGHT MODE
In this menu you can select the NIGHT MODE 
as the default display. You can also switch 
between the two display modes during a dive 
using the Underwater Menu described in 
section 9.9.
2.9.  DEEP STOP
Genius calculates a deep stop for air and 
nitrox dives only. The depth is defined as that 
at which the 5th compartment (27-minute half 
time) switches from ongassing to offgassing. 
Stopping at this depth during an ascent 
allows the first four tissues to offgas at a 
relatively high ambient pressure (theoretically 
preventing microbubble formation) without 
causing excessive nitrogen uptake in the other 
tissues. The deep stop, when calculated, is 
shown in the top right corner of the display, 
next to the current depth. The deep stop is 
optional, not carrying it out does not introduce 
any penalties and its duration is NOT included 
in the total ascent time.
This menu allows you turn off the calculation 
and display of the deep stop. The default 
setting is OFF.
2.10.  DECO STOP
This menu allows you to choose the depth of 
the shallowest stop among 3m/10ft, 4.5m/15ft 
and 6m/20ft. Decompression times increase 
when the shallowest stop is deeper.
2.11.  SECONDS
If set to ON, this menu allows you to add 
seconds to the dive time. Due to space 
limitations, this implies a size reduction of the 
information to the right of the dive time.
2.12.  LINKED MAP
In this menu, you can select a map which you 
can later on call up during the dive.
2.13.  ERASE DESATURATION
Genius allows you to reset the desaturation 
in the computer. Any tissue saturation 
information from a recent dive will be reset to 
zero and the computer treats the next dive as 
a non-repetitive dive. This is useful when the 
computer is loaned to another diver who has 
not dived in the last 24 hours. 
 WARNING
Diving after having reset the desaturation 
is extremely dangerous and is very likely to 
cause serious injury or death. Do not reset 
the desaturation unless you have a valid 
reason to do so.
Once inside the menu, you will see a graphic 
representation of the loading in all tissues 
of the decompression calculation. To prevent 
accidental desaturation reset, you must enter 
the security code once you decide to proceed 
with the reset. The security code is 1234. 
After entering the security code you will get a 
confirmation of the successful completion of 
the operation.
2.14.  ALL SILENT MODE
In this menu you can disable audible alarms.
 WARNING
Disabling audible alarms can lead you into 
potentially dangerous situation and could 
result in serious injury or death. 
2.15.  ASCENT VIOLATION 
If the ascent rate exceeds 120% of the allowed 
value over a depth change of more than 
20m/66ft, due to the potential of harmful 
bubble formation, Genius locks the computer 
for 24 hours in order to prevent you from diving 
again. In this menu, you have the option to 
disable the locking up of the computer in the 
event of an uncontrolled ascent. 
 WARNING
-  An uncontrolled ascent increases your 
risk of decompression sickness (DCS)
-  This feature is intended for very 
experienced divers only, such as dive 
instructors, who take full responsibility 
for the consequences of turning off this 
function.

GENIUS Dive Computer
10
• 3.  SET COMPUTER
MENU Description
SET COMPUTER
LANGUAGE
Allows you to set the language 
for the user interface, all 
menus and warning messages 
during the dive.
UNITS 
Allows you to choose between 
metric (m,°C, bar) and 
imperial (ft,°F, psi) units.
CLOCK
Allows you to set the date, 
time, time zone shift when 
travelling, and a wake-up 
alarm.
BRIGHTNESS
Allows you to set the 
maximum brightness of the 
backlight.
COMPASS 
DECLINATION
Allows you to compensate 
between magnetic north 
and geographic north in the 
digital compass.
COMPASS 
CALIBRATION
Allows you to recalibrate the 
compass.
3.1.  LANGUAGE
In this menu you can set the language for the 
user interface and for alarm messages during 
the dive.
3.2.  UNITS
You can choose between metric (depth in 
meters, temperature in°C, tank pressure in 
bar) and imperial (depth in feet, temperature 
in°F, tank pressure in psi). 
3.3.  CLOCK
This menu allows you to set the time format, 
time, date, time zone shift and wake-up alarm. 
3.4.  BRIGHTNESS
This menu allows you to change the brightness 
of the display to adapt to various levels of light 
conditions. Upon entering this menu, a sliding 
bar appears across the display. Use   and   
to set the brightness level. 
3.5.  COMPASS DECLINATION
Depending on the exact location on the planet, 
there can be a deviation between true North 
and magnetic North. Any compass will always 
show magnetic North, so via this menu you can 
set a value for the so-called declination that will 
make the compass show true North instead.
3.6.  COMPASS CALIBRATION
The digital compass in Genius is calibrated from 
the factory and does not require, under normal 
circumstances, any further maintenance. 
In certain instances, however, such as after 
exposure to extremely intense magnetic fields, 
it may be necessary to recalibrate the compass 
to ensure its accuracy. If you notice an obvious 
deviation in the indication of the compass, 
access this menu and perform the calibration 
as described below.
First you must enter the security code, 1234. 
Then the image shown in Figure 7 appears on 
the display.
Now hold Genius horizontal to the surface 
and perform one slow counter clockwise 
circle. Once you have finished the circle, the 
calibration is completed. 
• 4.  DIGITAL COMPASS
Genius has a tilt-compensated digital compass 
which can be used at almost any inclination. 
The compass can be called up at any moment 
during the dive and it can also be used on 
the surface. This menu allows you to use the 
compass on the surface and also to set a 
bearing for reference during your next dive. 
The number shown in the middle of the 
compass rose represents the bearing, between 
0 (North) and 359. 
4.1.  SETTING A BEARING
With   you can set a reference bearing. This 
is useful for instance if you are on a boat and 
there is a landmark on the shore that you can 
use for alignment to reach a specific spot on 
that dive site. Press   and a dot will appear 
to indicate the set bearing. Additional symbols 
will appear as well: squares at 90 degrees, 
triangles at 120 degrees and two parallel 
lines at 180 degrees, as an aid in navigation 
for square, triangular and reciprocal courses. 
The number at the bottom represents the 
deviation of the direction you are pointing at 
with reference to the set bearing.
Once underwater, align the dot with the arrow 
and start swimming in that direction. If you 
press   again, the new bearing will override 
the one in memory. If you press and hold   
you erase the bearing. 
• 5.  INFO
This submenu provides various information 
about the hardware and software of your 
Genius. It also lists information about the use 
of the dive computer, such as longest dive, 
deepest dive, total number of dives and total 
dive time. These can be individually reset to 
0 by pressing the right button (RESET). In 
addition, you can revert to the original settings 
configuration via the FACTORY RESET option 
(this option is not available while there is 
remaining desaturation in the computer). The 
option FACTORY MAINTENANCE is for use by 
authorized personnel only.
• 6.  MAPS AND PHOTOS
These menus allow you to view all the maps 
and pictures that have been uploaded via Dive 
Organizer to your Genius. Any file in JPEG 
format can be uploaded to Genius. Note that 
only the files listed as maps can be selected 
for the LINKED MAP function described in 
section 2.12.
The memory of Genius can hold approximately 
100 between maps and pictures.
• 7.  BUTTON LOCK
This function allows you to lock the buttons 
so that the computer is not turned on 
inadvertently. This is very useful for instance 
while travelling to a dive site, since otherwise 
Genius might unintentionally drain the battery 
before the dive. 
To lock the buttons, press and hold SELECT 
for one second from the main menu, or press 
it normally when the BUTTON LOCK icon is 
highlighted. This will blacken the display.
To unlock the buttons, press the left button 
followed by pressing the right button. The 
home display now reappears.

11
• PART II 
• 8.  DIVING WITH GENIUS
8.1.  A FEW WORDS ABOUT 
NITROX 
Nitrox is the term used to describe breathing 
gases made of oxygen-nitrogen mixes with 
an oxygen percentage higher than 21% (air). 
Because Nitrox contains less nitrogen than 
air, there is less nitrogen loading on the 
diver’s body at the same depth as compared to 
breathing air. 
However, the increase in oxygen concentration 
in Nitrox implies an increase in oxygen partial 
pressure in the breathing mix at the same 
depth. At higher than atmospheric partial 
pressures, oxygen can have toxic effects on the 
human body. These can be lumped into two 
categories:
-  Sudden effects due to oxygen partial 
pressure over 1.4bar. These are not related 
to the length of the exposure to high partial 
pressure oxygen, and can vary in terms of the 
exact level of partial pressure they happen 
at. It is commonly accepted that partial 
pressures up to 1.4bar are tolerable, and 
several training agencies advocate maximum 
oxygen partial pressures up to 1.6bar. 
-  Long exposure effects to oxygen partial 
pressures over 0.5bar due to repeated and/
or long dives. These can affect the central 
nervous system, cause damage to lungs or 
to other vital organs. 
Genius keeps you safe with respect to these 
two effects in the following ways (as long as it 
is set to either AIR or NITROX): 
•  Against sudden effects: Genius has an MOD 
alarm set for a user-defined ppO2max. As 
you enter the oxygen concentration for the 
dive, Genius shows you the corresponding 
MOD for the defined ppO2max. The default 
value of ppO2max from the factory is 1.4bar. 
This can be adjusted to your preference 
between 1.2 and 1.6bar. Please refer to 
section 2.1 for more information on how to 
change this setting. If Genius is set to AIR, 
the ppO2max is set to 1.4bar by default.
•  Against long exposure effects: Genius 
“tracks” the exposure by means of the 
CNS% (Central Nervous System). At levels 
of 100% and higher there is risk of long 
exposure effects, and consequently Genius 
will activate an alarm when this level of 
CNS% is reached. Genius also warns you 
when the CNS level reaches 75%. Note that 
the CNS% is independent of the value of 
ppO2max set by the user.
8.2.  ALTITUDE
Atmospheric pressure is a function of altitude 
and of weather conditions. This is an important 
aspect to consider for diving, because the 
atmospheric pressure surrounding you has an 
influence on uptake and subsequent release 
of nitrogen. Above a certain altitude, the 
decompression algorithm has to change in 
order to account for the effect of the change in 
atmospheric pressure. Genius automatically 
adapts the algorithm by sensing the ambient 
pressure every 20 seconds even when it is 
turned off.
NOTE
We do not recommend diving at altitudes 
above 3700m / 12100ft. If you do, set 
Genius to BOTTOM TIMER and find 
appropriate altitude dive tables. 
8.3.  LOGBOOK
From the home screen, press the LOG button 
to access the logbook.
Genius can record the profiles of over 1000 
hours of diving, at a sampling rate of 5 
seconds. The information can be transferred 
to a Smartphone (MySSI app, via bluetooth), 
PC (Dive Organizer software, Bluetooth or USB 
cable) or Mac (DiversDiary software, Bluetooth 
or USB cable). In addition, Genius can show 
most of the information directly on the display. 
On the main page of the logbook you will see a 
listing of all dives, including date, time the dive 
started, depth and dive time.
By pressing SELECT you will access the details 
of the dive, and from here you can view the 
depth profile with either the temperature or 
tank pressure data by pressing PROFILE. 
8.4.  DIVE PLANNER
From the home screen, press and hold the 
PLAN button to access the dive planner. 
This function allows you to plan your next dive. 
In case you dived recently, you can enter an 
additional surface interval between now and 
when you intend to dive: the residual nitrogen 
load will be adapted accordingly. Genius will 
consider all active gases and set gradient 
factors, listed for reference at the top of the 
screen. Hit the SELECT button then use the   
and   buttons to define the additional surface 
interval in 15-minute increments. Next hit 
BACK and use the   and   buttons to scroll 
through the no decompression limits for all 
depths, in 3m / 10ft increments, up to the 
MOD for the gas in use. If you wish to see what 
would happen if for a given depth you extended 
your dive time beyond the no decompression 
limit, press the right button, labelled DECO. 
Use the   to increase your dive time and 
see what your corresponding decompression 
obligation would be. Press BACK to return to 
the no decompression limits.
8.5.  ALARMS
Genius can alert you of potentially dangerous 
situations. There are six different alarms:
-  Ascent rate alarm;
-  Exceeding a safe ppO2/MOD;
-  CNS =75%; 
-  Missed decompression stop;
-  Low tank pressure/RGT < 3 min;
-  Low battery during the dive.
 WARNING
When in bottom timer mode, all warnings 
and all alarms are OFF aside for the low 
battery alarm.
NOTE
-  Alarms are both visual and audible, as 
described in detail below.
-  If you are in any graphic display mode 
(compass, dive profile, map viewing or 
tissue graph) when an alarm is triggered, 
you will be kicked out of that mode and 
back to the standard numeric display.
-  Ascent rate alarm has priority over 
other alarms if they are triggered 
simultaneously.
8.5.1.  ASCENT RATE 
As soon as depth decreases Genius activates 
the ascent rate control algorithm and displays 
the calculated value both numerically and 
graphically.
 WARNING
A rapid ascent increases the risk of 
decompression sickness. 
If Genius determines an ascent rate higher 
than set limits, the fast ascent alarm is 
triggered: an audible alarm goes off, the 
arrows on the left side bar turn red and the 
message SLOW DOWN is displayed in the 
middle of the screen of the screen (Fig. 8). 
This persists until the ascent rate is reduced 
to below the pertinent limit. The limits are 
dependent on the current depth as follow:
Depth 
in m
Speed in 
m/min
Depth in 
feet
Speed in 
ft/min
> 50 m
20 > 165 ft 60
30 – 50 m 15
100 – 165 ft
45
10 – 30 m 10
30 – 100 ft
30
< 10m 5 < 30ft 15

GENIUS Dive Computer
12
 WARNING
If the ascent rate exceeds 120% of the 
allowed value over a depth change of 
more than 20m/66ft, due to possible 
harmful bubble formation, Genius locks 
the computer for 24 hours in order to 
prevent you from diving again. You can 
disable this function in the menu ASCENT 
VIOLATION. This should only be done by 
highly experienced divers, who take full 
responsibility for the consequences of this 
action.
8.5.2.  MOD/ppO2
 WARNING
-  The MOD should not be exceeded. 
Disregarding the alarm can lead to 
serious injury or death.
-  Exceeding a ppO2 of 1.6bar can lead to 
sudden convulsions resulting in serious 
injury or death. 
When the diver reaches a depth at which the 
ppO2 of the inspired gas exceeds the maximum 
limit entered in the corresponding setting 
(from 1.2 to 1.6bar), an audible alarm goes off, 
the depth is shown in red and the message 
MOD EXCEEDED is shown at the bottom of the 
display (Fig. 9).
The alarm persists until the diver has 
ascended enough for the ppO2 to return within 
the set limit. While the alarm is active, the 
map function is disabled and the compass can 
only be called up for 10 seconds, after which 
the default display with the alarm message 
is shown again. The gas switch menu can be 
called up for 20s before the display switches 
back to the alarm message.
 WARNING
When the MOD alarm is triggered, ascend 
immediately until the alarm stops. Failure to 
do so could result in serious injury or death.
8.5.3.  CNS = 75%
 WARNING
When the CNS reaches 100% there is 
danger of oxygen toxicity. Genius starts 
alerting you when you reach 75%.
Oxygen toxicity exposure is tracked on 
Genius by means of the CNS% based on 
currently accepted recommendations for 
exposure limits. Thistoxicity is expressed as 
a percentage value which ranges from 0% to 
100%. When the value exceeds 75%, it turns 
red and the warning message CNS > 75% 
appears on the display until you hit any button 
to acknowledge having seen it. Furthermore, 
the field which can be selected via the   
button shows the CNS value in red. If you push 
the   button to view any other value, it will 
remain for 4s only, and then return to the CNS 
value (Fig. 10).
If the oxygen toxicity level reaches 75%, ascend 
to shallower depth to decrease oxygen loading 
and consider terminating the dive.
 WARNING
Diving with oxygen toxicity at levels of 75% 
or greater may put you into a potentially 
hazardous situation, which could result in 
serious injury or death.
8.5.4.  MISSED DECOMPRESSION STOP
 WARNING
Violating a mandatory decompression 
obligation may result in serious injury or 
death. 
If you ascend above the decompression stop 
depth by more than 0.3m (1ft), an audible 
alarm goes off and the message BACK TO 
STOP DEPTH is displayed at the bottom of the 
screen (Fig. 11). This alarm remains active 
until you return to the correct depth. Note 
that while the alarm is active, it is not possible 
to consult the map, and the compass can be 
viewed only for 10 seconds before the screen 
returns to the default display.
 WARNING
Never ascend above the displayed 
decompression stop depth.
8.5.4.1. MISSED DECO STOP MODE
If the stop depth is exceeded by less than 1m 
(3ft) for more than threeminutes or by more 
than 1m (3ft) for more than 1 minute, Genius 
considers it a dive violation and the display will 
show VIOLATION - DECO.
In this case, if the diver attempts a repetitive 
dive after surfacing, Genius will function 
only as a depth gauge and timer (bottom 
timer mode), and it will display the message 
LOCKED BY PREVIOUS DIVE.
8.5.5.  LOW TANK PRESSURE / RGT < 3 MIN
If GAS SUPPLY ESTIMATE in 2.3 is set to TTR:  
When during a decompression dive Genius 
calculates a TTR which is inferior to the 
total ascent time, the message LOW TANK 
PRESSURE appears on the bottom of the 
display and remains there until you hit any 
button to acknowledge having seen it (Fig 12a). 
We strongly suggest initiating an ascent when 
this situation arises, in order to avoid running 
out of breathing gas during the decompression 
stop.
If GAS SUPPLY ESTIMATE in 2.3 is set to RGT: 
When during a decompression dive Genius 
calculates an RGT of 3 minutes or less, the 
message RGT < 3 min appears at the bottom 
of the display and remains there until you hit 
any button to acknowledge having seen it (Fig. 
12b). We strongly suggest initiating an ascent 
when this situation arises.
Additionally, when the tank pressure reaches 
the value specified under TANK RESERVE, 
the message TANK RESERVE REACHED 
is displayed until you hit any button to 
acknowledge having seen it (Fig. 13).
8.5.6.  LOW BATTERY
 WARNING
Do not start a dive if the LOW BATTERY 
message is displayed on the screen on the 
surface. The computer may fail to function 
during the dive and this could lead to 
serious injury or death.
If Genius detects that the battery power 
level is getting low, it will show the message 
LOW BATTERY on the display until you hit 
any button to acknowledge having seen it. 
Furthermore, the lower right corner shows 
the battery information in red (Fig. 14). If you 
push the   button to view any other value, it 
will remain for 4s only, and then return to the 
battery value. In a LOW BATTERY situation, the 
map function is disabled, as well as audible 
signals, and the backlight is reduced to a low 
power safety level (readability of the display is 
ensured). You can still access the compass, but 
after 30s the screen will revert to the standard 
display and the battery displayed in red. 
 WARNING
When this warning appears, you should 
stop the dive, safely, without delay. 
If the battery is completely drained during 
or right after a dive, Genius will lose the 
nitrogen loading information in the tissues, 
and hence it will calculate the next dive 
wrongly. Do not dive for 24 hours following 
a dive during or after which the battery was 
completely drained.
In addition to monitoring the status of its own 
battery, Genius also monitors the status of the 
battery in all tank modules paired to it, and 
alerts you when a battery is low and should 
be replaced. The message G1 (or G2 through 
G5) LOW BATTERY is displayed until you hit 
any button to acknoweldge having seen it. 
Furthermore, the lower right corner shows 
the tank module battery information in red 
(Fig. 15). If you push the   button to view any 
other value, it will remain for 4s only, and then 
return to the tank module battery information. 
• 9.  DISPLAY INFORMATION
From the home menu, press the left button to 
enter PRE-DIVE mode. This will ensure that 
Genius starts to monitor the dive as soon as 
a depth of 1.2m/4ft is reached. If you start 
the dive without putting Genius into pre-dive 
mode, Genius will switch into dive mode 
automatically but with a delay of up to 20 
seconds from immersion.
NOTE
-  If you remain in pre-dive for longer than 
10minutes without pressing any button, 
Genius will switch off.
-  It is recommended to put Genius into 
pre-dive before submerging. Not doing 
so can lead to a delay of up to 20s in 
Genius monitoring the dive.
Upon immersion, if Genius was set to pre-
dive, it will immediately start monitoring the 
dive. Otherwise, it will turn on automatically 

13
within 20 seconds of having reached a depth of 
1.2m/4ft. 
With Genius you have a choice of how the 
information is presented on the display. 
The standard display presents dive information 
in a prevalently numerical format. More 
specifically, the following information is 
displayed (Fig. 16):
-  current depth and temperature in top row
-  no deco time in middle row (depth of 
deepest stop, time at deepest stop and total 
ascent time in case of decompression dives)
-  dive time and active gradient factors in 
bottom row
-  description of gas in use, tank pressure in 
bar / psi, graphic representation of tank 
pressure using the 4 color ranges described 
in section 2.3.1, time to reserve (TTR) or 
remaining gas time (RGT) along the right 
edge of the display
-  nitrogen bar graph along the left edge of the 
display
-  ascent speed: in case of an ascent, the value 
in m/min or ft/min is displayed in lieu of the 
dive time, while graphically it is shown in 
lieu of the nitrogen bar graph (each arrow 
representing 20% of the allowed limit).
Upon pressing  , the field to the right of the 
current depth is modified in the following 
sequence:
-  max depth
-  average depth
-  MOD of gas in use
-  deep stop if active and calculated
-  ASC + X
- ceiling.
Upon pressing  , the field to the right of 
the dive time is modified in the following 
sequence: 
-  current gradient factor/gradient factor at 
the surface if the diver ascends now
- stopwatch
-  CNS (Nitrox only)
- ppO2 (Nitrox only)
-  time of day
-  battery status of Genius
-  battery status of tank module in use
-  gas consumption in l/min or cuft/min.
NOTE
if you set Genius to AIR, the information on 
MOD, CNS and ppO2 are not displayed in 
order to simplify the display. The CNS value 
is however calculated in the background 
and both the CNS alarm and MOD alarm 
are triggered if the circumstances require 
it. If you are diving air but would anyway 
like to see the MOD, CNS and ppO2, set 
Genius to Nitrox 21%.
The battery in the tank module is shown as 
a battery outline with either 3 (battery ok), 2 
(battery ok for now but you should consider 
replacing it) or 1 (battery could fail any time) 
segments inside of it. The 3-segment situation 
is green, the 2-segment situation is yellow, 
and the 1-segment situation is red.
9.1.  DETAILED DESCRIPTION OF 
DISPLAYED DATA
The depth is given in 10cm resolution until 
99.9meters, after which it is given in 1m 
resolution. When the depth is displayed in 
feet, the resolution is always 1 foot. At a depth 
shallower than 1.2m/4ft, the display shows ---. 
Maximum possible depth is 150m/492ft. 
The dive time is displayed inminutes. If during 
the dive you ascend to the surface, the time 
spent on the surface will only be counted 
if you descend again below 1.2m/4ft within 
3minutes. This allows for brief periods of 
orientation. While on the surface, the time will 
not show as progressing but it is running in 
the background. As soon as you submerge, the 
time will resume, including the time spent on 
the surface. 
The no deco time is calculated in real time and 
updated continuously. Maximum displayed 
no deco time is 99minutes. If you remain at 
depth beyond a no deco time of zerominutes, 
you will enter into decompression: you can no 
longer make a direct ascent to the surface and 
Genius displays a MANDATORY decompression 
stop. Instead of a no deco time, it shows you 
the depth of the deepest stop, the time at the 
deepest stop, and the total ascent time (ASC), 
which includes each decompression stop and 
the time required to travel the vertical distance 
to the surface at the allowed rate (Fig. 17). ASC 
does NOT include the duration of deep stops. 
Deep stops are NOT mandatory so you can 
skip them without incurring any penalty in the 
decompression calculation.
Once there is a mandatory decompression 
stop, the second button from the left features a 
new label:  . Pressing and holding it will 
display the details of all stops computed by 
Genius, up to a maximum of 4, starting from 
the deepest (Fig. 18).
The tank pressure is based on the signal from 
the tank module. The tank module has a range 
of 1.5m/5ft. In addition to showing the numeric 
value, Genius employs color coding to identify 
a range in tank pressure, as described in 
section 2.3.1
 WARNING
-  If Genius receives no signal from 
the tank module for 45 seconds, the 
pressure value is replaced by ---. Check 
the position of Genius with respect to the 
tank module. Start ascending if you don’t 
get a tank pressure reading unless you 
have a spare pressure gauge.
-  If the tank pressure reaches 
10bar/145psi, the tank module will 
turn off and Genius will not show tank 
pressure any longer. 
NOTE
Genius needs approximately 2minutes to 
analyze your breathing pattern, thus the 
TTR or RGT is not displayed at the very 
beginning of the dive.
The nitrogen bar graph is on the left 
side of the display. It represents nitrogen 
supersaturation (any amount in excess of the 
equilibrium state at the surface) in the leading 
tissue compartment. The bar graph is made 
of ten segments, which gradually switch from 
green to red during the dive. The more red 
segments you see, the closer to the no deco 
limits you are. As you enter a situation of 
mandatory decompression stop, all segments 
will be red. 
During a surface interval, the segments 
will gradually turn off as Genius tracks the 
offgassing of your tissues.
Ascent rate: in presence of a depth change 
in excess of 80cm / 3ft, Genius calculates the 
corresponding ascent speed and displays both 
numerically (in lieu of the dive time) and via an 
arrow bar which, for the duration of the ascent, 
replaces the nitrogen bar graph. Each arrow in 
the arrow bar represents 20% of the allowed 
rate. These arrows turn red for speeds in 
excess of the allowed limit described in section 
8.5.1.
The current gradient factor (GF NOW) is the 
highest value of inert gas supersaturation 
among all 16 tissues of the algorithm at the 
present moment. The gradient factor at the 
surface if the diver ascends now (GF @ SURF) 
is the value of supersaturation that at least 
one tissue will reach if you were to ascend now 
at the allowed ascent rate disregarding any 
deco and safety stop (Fig. 19). 
The ceiling is the depth at which you would 
exceed the gradient factor. As you clear a stop 
and begin the next one, the ceiling is the same 
as or very close to the stop depth itself. As the 
duration of the stop decreases, so does the 
ceiling until it reaches the depth of the next 
stop.
The stopwatch can be reset by pressing and 
holding   when the stopwatch is displayed. 
This will also set a bookmark in the dive profile 
memory.
9.2.  DEEP, DECO AND SAFETY 
STOPS
DEEP stops are generated as you approach the 
no deco limit. DEEP stops are NOT mandatory 
but rather suggestions which attempt to 
minimize bubble production by offgassing 
some nitrogen at high ambient pressure. Deep 
stops are shown to the right of the current 
depth (Fig. 20).
DECO stops are generated progressively as 
you stay at depth beyond the no deco time. 
DECO stops are MANDATORY As you approach 
the depth of a stop, the duration of the stop 
is gradually reduced. The duration itself is 
always shown in minutes, and is calculated as 
a function of the pressure gradient achieved at 
the stop depth itself. Hence the farther you are 
from the exact depth of the stop, the longer it 
will take for each minute to tick off. 
A SAFETY stop is generated as soon as the 
depth of the dive exceeds 10m / 33ft. It has 
a duration of 3minutes and it is carried 
out between depths of 6m / 20ft and 3m / 
10ft at the end of a dive prior to surfacing. 
Such stop is NOT mandatory but HIGHLY 
RECOMMENDED. A safety stop is always 
shown as a 3-minute countdown in minutes 
and seconds (Fig. 21).

GENIUS Dive Computer
14
 WARNING
During all dives, perform a safety stop 
between 3 and 5 meters/10 and 15 feet for 
3minutes, even if no decompression stop 
is required.
9.3.  FUTURE DECOMPRESSION
In case of a decompression dive, the   
sequence also features ASC+5. The value 
shown represents the total ascent time if 
you were to remain at the current depth for 
an additional 5 minutes. This is very useful 
since it allows you to estimate how your 
decompression will be affected by remaining at 
the current depth a while longer (Fig. 22).
It is also very useful because, as the slower 
tissues start accumulating nitrogen, you 
could find yourself in a situation in which 
the decompression time grows very quickly, 
so much so that you may find yourself with 
insufficient gas to finish the dive.
NOTE
Associated to a large difference between 
the current ASC and the ASC+5 value, 
Genius will alert you with the RUNAWAY 
DECO warning: since the ASC+5 calculation 
runs in the background and is permanently 
updated, Genius monitors this value and, 
if it is calculated to be greater than 10 
minutes beyond the current ASC, Genius 
will trigger the alarm RUNAWAY DECO. 
This remains on the display until you press 
any button to acknowledge having seen it 
(Fig. 23). 
NOTE
The prediction of ASC can be set between 
3 and 10 minutes in advance via the ASC+X 
menu within FUTURE DECO in SET DIVE. 
The value of X can be set between 3 and 10 
minutes.
Likewise, the trigger point of the 
RUNAWAY DECO alarm can be set between 
2 and 4 times the value of X. As an 
example, if you set the prediction of ASC 
to a value of +6 and the RUNAWAY DECO 
to a value of 3, the alarm will be triggered 
when the difference between the current 
ASC and the predicted one 6 minutes later 
is 6*3=18 minutes or greater.
9.4.  DIVE PROFILE 
During the dive you can view the depth profile 
performed so far by pressing  . The profile is 
updated every 20 seconds. The top row now 
shows current depth and no deco time (or total 
ascent time in case of decompression dives, in 
which case the profile shows also all 
decompression stops) so that you can keep the 
profile on the display and still have all the 
major information about the dive (Fig. 24).
With the   button you can call up one 
additional piece of information but, unlike in 
the standard display, you can also remove it (by 
clicking through the whole sequence) in case it 
overlaps with the dive profile.
NOTE
The display remains in dive profile mode 
until you press   or until an alarm is 
triggered, in which case the display reverts 
to the standard display.
9.5.  COMPASS 
During the dive you can access the compass 
by pressing  . In COMPASS mode, the top 
row of the display shows current depth and no 
deco time (or total ascent time in the case of 
decompression dives), so that you can keep the 
compass on the display and still have all the 
major information about the dive (Fig. 25). 
With  , you can set a reference bearing. A 
dot will appear to indicate the set bearing. 
Additional symbols will appear as well: 
squares at 90 degrees, triangles at 120 
degrees and two parallel lines at 180 degrees, 
as an aid in navigation for square, triangular 
and reciprocal courses. The number at 
the bottom represents the deviation of the 
direction you are pointing at with reference to 
the set bearing. If you press   again, the new 
bearing will override the one in memory. If you 
press and hold   you erase the bearing. 
By pressing  , the top row is split in two and 
a stop watch appears in the lower row. Use 
 to activate the stop watch. Every time you 
press  , the stop watch restarts from 00:00. 
By pressing  , the top row goes back to full 
size but the stop watch keeps running in the 
background (Fig. 26).
NOTE
The display remains in compass mode until 
you press   or until an alarm is triggered, 
in which case the display reverts to the 
standard display.
9.6.  TISSUE SATURATION GRAPH
By pressing and holding the right button ( ) a 
complete description of the current tissue 
saturation fills the space underneath the top 
row. The top row itself shows current depth 
and no deco time (or total ascent time in case 
of decompression dives) so that you can keep 
the tissue saturation graph on the display and 
still have all the major information about the 
dive (Fig. 27). The graph itself is updated 
continuously.
The graph shows the tissue tension in each 
of the 16 compartments simulated by the 
algorithm, both the instantaneous value (left 
bar, green or yellow) and the projected value at 
the surface after an ascent at the allowed rate 
(right bar, blue or red) together with dotted 
lines representing the maximum tolerated 
supersaturation values at the surface and, 
in presence of decompression stops, at the 
depth of all calculated stops. The vertical axis 
represents pressure. As long as the right bar 
(projected value at the surface) remains below 
the dotted line, that particular tissue does not 
require decompression. When one of the right 
tissues pushes past the lower dotted line, a 
decompression stop will be required (failure 
to meet the safe ascent criterion) and the bar 
itself changes from blue to red. If a right bar 
were to push past the second dotted line, there 
would be a 6m / 20ft stop required in addition 
to a 3m / 10ft stop.
For air and nitrox dives, on the graph there is 
also a horizontal black line: this represents, on 
the same pressure scale, the partial pressure 
of nitrogen in the inhaled gas. The distance 
between the line and the left bar represents 
the pressure difference driving gas in or out 
of a tissue and is thus indicative of the speed 
of on or offgassing. As long as the line is 
above the left bar, the tissue in question is 
taking on gas and the bar is depicted in yellow. 
Once the line descends into the left bar, the 
tissue in question is offgassing and the bar 
becomes green. More information about 
this can be found in the download section of 
www.mares.com.
9.7.  DECO SUMMARY TABLE
From the tissue saturation graph, press   to 
view the DECO SUMMARY TABLE. This shows 
the following four decompression calculations 
(Fig. 28):
-  the predictive multigas decompression 
schedule for the MAIN GF values (not 
available for single gas dives)
-  the decompression calculation assuming the 
dive is finished with the gas currently active, 
for the MAIN GF values
-  the predictive multigas decompression 
schedule for the ALTERNATE GF values (not 
available for single gas dives)
-  the decompress ion calculation assuming 
the dive is finished with the gas currently 
active, for the ALTERNATE GF values.
This gives you an overview of all the 
alternatives available to you in case you ran 
out of one or more gases and/or you decided to 
switch to the alternate GF values.

15
9.8.  VIEWING MAPS DURING A 
DIVE
To call up the map selected under SET 
DIVE/LINKED MAP, press   from the 
decompression summary table. The map will 
remain on the display for 10 seconds, after 
which the screen reverts to dive information. 
You can press   to return to the main screen 
before the 10 seconds have elapsed (Fig. 29).
NOTE
-  In the event of an alarm, Genius 
automatically switches back to the 
standard display.
-  The map is static, and does not change 
as you swim during the dive.
9.9.  UNDERWATER MENU
By pressing and holding the left button ( ) you 
can call up a menu which allows you to change 
certain settings during the dive. These are 
described in detail in section  although some 
names have changed a bit due to the limited 
length available in the UW menu (Fig. 30).
BOOKMARK - allows you to set a bookmark 
which you can later review in the downloaded 
dive profile
AIR (or G1) - corresponds to MODE in 2.1. This 
is meant for those occasions when you forgot 
to update the oxygen percentage setting in the 
computer after a change of nitrox, a switch 
from air to nitrox or viceversa, which would 
force you to abort the dive or at least go to the 
surface, wait three minutes to exit the dive and 
then perform the change. This menu is active 
only during the first minute of the dive and only 
if the depth has not exceeded 6m / 20ft.
NOTE
This menu is not meant for switching to a 
high oxygen content decompression gas. 
GF DIVE - as described in 2.2.3
LINKED MAP - as described in 2.12
NIGHT MODE - as described in 2.8
FUTURE DECO - as described in 2.6
MAX DEPTH - as described in 2.4.1
DIVE TIME - as described in 2.4.2
BRIGHTNESS - as described in 3.4
TANK VOLUME - as described in 2.3
MAX PRESSURE - corresponds to OPERATING 
TANK PRESSURE in 2.3
HALF TANK - corresponds to MID TANK 
WARNING in 2.3
TANK RESERVE - as described in 2.3
WATER - as described in 2.7
• 10. AFTER THE DIVE
Upon returning to the surface, Genius first 
goes into the so-called surfacing mode. This 
mode allows you to resume your dive after a 
brief period of orientation. The screen shows 
a 3-minute countdown, a profile of the dive, 
your maximum depth, dive time, average depth 
and, for nitrox dives, the CNS% at the end of 
the dive. When used with the optional tank 
module, the screen shows the tank pressure 
as well (Fig. 31).
If you submerge again before the 3-minute 
countdown is over, the dive time will resume 
from where it left off, including the time spent 
on the surface. If you do not submerge before 
the end of the countdown, Genius considers the 
dive finished, records the data to the logbook 
and reverts to the so-called post-dive mode.
The post-dive screen shows the following 
information (Fig. 32):
-  The remaining desaturation time (DESAT): 
this is calculated by the decompression 
model in the computer. Any dive started 
while there is remaining desaturation on 
your computer is considered a repetitive 
dive, meaning that Genius accounts for the 
pre-existing nitrogen load in your body. 
-  The no-fly time (NO-FLY): this is the time 
during which an exposure to the reduced 
pressure inside the cabin of an airplane 
could cause decompression sickness. 
Genius calculates this as the time it takes 
for the tissue tension in all compartments to 
be compatible with an ambient pressure of 
0.55bar (corresponding to a depressurized 
airplane cabin).
 WARNING
Flying while Genius displays NO-FLY can 
result in serious injury or death. 
-  The surface interval (SURF. INT.): this is 
displayed from the moment the dive is 
closed (3minutes after surfacing) for as 
long as there is remaining desaturation or 
no-fly time on the computer. 
-  CNS: this allows you to track how the CNS 
load from the previous dive is gradually 
reduced during the surface interval.
The screen also shows the main data of the 
last dive: max depth, temperature, dive time, 
initial and final tank pressure.
In addition, the supersaturation with respect 
to ambient pressure at the surface in all 16 
compartments of the algorithm is shown 
discretized in ten segments. The tallest bar is 
also reproduced along the left edge in the same 
fashion as it is also during the dive. You can 
use this to gauge your progress in getting rid of 
nitrogen as the surface interval grows. Genius 
continues to perform decompression-related 
calculations (inert gas release), for as long as 
there is desaturation or no-fly time left. 
• 11. DIVING WITH MORE THAN ONE 
GAS MIXTURE
 WARNING
-  Diving with more than one gas mixture 
represents a much higher risk than 
diving with a single gas mixture, and 
mistakes by the diver may lead to 
serious injury or death.
-  During dives with more than one gas 
mixture, always make sure you are 
breathing from the tank that you intend 
to breathe from. Breathing from a high 
oxygen concentration mix at the wrong 
depth can kill you instantly.
-  Mark all your regulators and tanks so 
that you cannot confuse them under any 
circumstance.
-  Before each dive and after changing 
a tank, ensure that each gas mixture 
is set to the correct value for the 
corresponding tank.
Genius enables you to use up to three gas 
mixtures during the dive (air and Nitrox 
only). The three mixtures are labeled G1, G2 
and G3 and must be in ascending order of 
oxygen content, i.e. G1 has the lowest oxygen 
concentration, G2 an intermediate value, and 
G3 has the highest oxygen concentration of the 
three. Two or more tanks can also be set to the 
same oxygen concentration. If you are diving 
with only two mixtures, you will be utilizing 
tanks G1 and G2. 
Genius can be set to consider all active gases 
in the decompression calculation, or it can 
be set to consider only the gas currently in 
use. In the first case (PREDICTIVE = ON in 
2.5.1), when you switch gas when prompted 
to do so during an ascent, you will not see 
a change in the decompression calculation: 
Genius considered that you were going to 
switch gas and already considered the effect 
of this on the decompression. In the second 
case (PREDICTIVE = OFF in 2.5.1) you will see 
a reduction in the total ascent time as you 
switch to a gas with higher oxygen content and 
Genius considers this for the decompression 
calculation.
Genius can show the tank pressure of each 
tank if the corresponding first stage regulator 
is equipped with a Mares tank module, paired 
as described in section 1.8. Note that Genius 
can be programmed and used for diving with 
more than one gas mixture whether you use 
tank modules for each or not.
NOTE
You can set all the gases to the same 
oxygen percentage. 

GENIUS Dive Computer
16
11.1.  SETTING MORE THAN ONE GAS
The characteristics of the gases must be 
entered in the computer before the dive. Itwill 
then be your responsibility to tell Genius which 
gas is currently being used during the various 
phases of the dive. 
NOTE
-  If you dive using just one gas, select G1 
and deselect the other two. 
-  For dives with two gases, select G1 and 
G2 and deselect the third. 
-  When enabling G2 and G3, you must first 
define G2 and then G3.
-  You cannot activate G3 without first 
having activated G2.
-  G2 cannot have an oxygen percentage 
higher than G3.
-  If you set G2 to OFF, G3 will 
automatically be set to OFF also.
-  The MOD for G2 and G3 is the switch 
depth for the corresponding gas. This 
is what Genius uses for its calculation, 
alarms and suggested switch points.
-  Setting a tank to OFF does not affect 
the pairing of the corresponding tank 
module.
To use multiple gases, you will need to enable 
the gases and set the oxygen percentage 
and the ppO2max for each one, as described 
in Figure 33. Keep in mind that the MOD for 
G2 and G3 is the depth at which Genius will 
prompt you to perform the gas switch (see 
section 11.2 below).
11.2.  SWITCHING GAS
During Nitrox dives with the gas switching 
function enabled, the third button from the left 
has two functions, indicated by a double icon: 
•  Press: scrolls through the sequence of 
information to the right of the dive time  . 
•  Press and hold: displays the gas switch 
screen  . 
Genius always begins the dive with G1, 
which has the lowest percentage of oxygen. 
When during the ascent you reach the depth 
corresponding to the MOD of G2, Genius sounds 
an audible signal and displays the message 
SWITCH TO GAS G2 below the top row (Fig. 
34). The left button now has label NO while 
the second and the third button have label OK. 
Press or press and hold either of the OK buttons 
to perform the switch, at which point Genius 
shortly displays the message GAS SWITCH OK; 
press or press and hold the NO button to stay on 
the current gas, at which point Genius shortly 
displays the message GAS NOT SWITCHED. If 
you don’t perform any action within 30 seconds, 
Genius shows GAS NOT SWITCHED and returns 
to the normal display. If set to PREDICTIVE = 
ON and the gas was not switched, Genius will 
show the message EXCLUDING GAS G2 prior 
to changing the decompression calculation to 
reflect the exclusion of G2.
If you drop again below the MOD for G2, Genius 
will show the message INCLUDING GAS 
G2 AGAIN and changes the decompression 
calculation accordingly.
NOTE
The same process is repeated when you 
approach the MOD for G3 with the message 
SWITCH TO GAS G3
You can always perform a manual switch, by 
pressing and holding  . This will make the gas 
switch screen appear, which shows all active 
gases (Fig. 35). 
NOTE
You can reach this screen at any time 
during the dive, for instance to check on 
the tank pressure and the planned switch 
point of G2 and G3.
Press   to scroll through the available gases, 
then press   to activate it. The decompression 
calculation will reflect the switch in breathing 
gas. In addition, the display will now show 
the symbol of the new gas and its oxygen 
concentration. In profile view, the area below 
the MOD of the deco gas is depicted in red.
NOTE
-  You can select another gas using  , if 
permitted at that depth.
-  You can exit this mode without changing 
the gas by pressing  .
-  If there is only one gas set, the computer 
will not enter this menu.
11.3.  SPECIAL SITUATIONS
11.3.1.  SWITCHING BACK TO A GAS 
MIXTURE WITH LOWER OXYGEN 
CONCENTRATION
There may be situations in which you have 
to switch back to a gas with lower oxygen 
concentration than what you are currently 
breathing. This can happen for instance if you 
want to descend deeper than the MOD for the 
current gas, or if for instance you have run out 
of gas in G3 during the decompression. To do 
so, simply press and hold   to call up the gas 
switch screen. Use   to choose another gas, 
then press   to activate it. The decompression 
calculation will reflect the switch in breathing 
gas.
11.3.2.  SUBMERGING BELOW THE MOD 
AFTER A GAS SWITCH 
If after having switched to a gas mixture with a 
higher oxygen concentration you inadvertently 
drop again below the MOD for that mixture, 
the MOD alarm will immediately go off. Either 
switch back to a gas mixture suited for that 
depth, or ascend above the MOD for the gas 
mixture you are breathing from. 
11.3.3.  RGT WHEN DIVING WITH MORE THAN 
ONE GAS MIXTURE
Genius determines the RGT based on your 
breathing pattern, the tank pressure for the 
gas you are currently breathing, and the 
decompression time calculated for that gas 
only. It does not account for tanks other than 
what you are currently breathing from, hence 
your actual autonomy may be higher. For this 
reason when diving with more than one gas 
mixture the RGT = 3 min is a soft warning and 
not an alarm.
11.3.4.  LOGBOOK FOR DIVES WITH MORE 
THAN ONE GAS MIXTURE
For dives carried out with more than one gas 
mixture, Genius adds information on oxygen 
concentration, initial, final and differential 
pressure for all gases used. On the dive profile, 
switch points are shown on the time line.
11.4.  DIVING WITH MORE THAN 
ONE GAS MIXTURE  TRIMIX 
OR HELIOX
Genius allows you to set up to 5 gases in which 
in addition to the oxygen percentage you can 
also set the helium percentage. In the tissue 
saturation graph you will see bars for the 
nitrogen partial pressure and for the helium 
partial pressure. Everything else is the same as 
with multigas nitrox diving with the addition of 
OTUs (Oxygen Toxicity Units) in the   sequence.
• 12. BOTTOM TIMER MODE
When Genius is set to BOTTOM TIMER mode, 
it will only monitor depth, time, tank pressure 
and temperature, and will not carry out any 
decompression calculation. You can only 
switch to bottom timer mode if the computer is 
completely desaturated. All audible and visual 
alarms, other than the low battery alarm, are 
turned off.
 WARNING
Dives in gauge mode are performed at your 
own risk. After a dive in bottom timer mode 
you must wait at least 24 hours before 
diving using a decompression computer.
During a dive in gauge mode, the following 
information is displayed (Fig. 36):
-  current depth
-  max depth
-  average depth
- stopwatch
-  dive time
- temperature 
-  time of day
-  battery status
-  tank pressure
-  in case of an ascent: ascent speed (in m/min 
or ft/min). 
The stop watch is reset by means of  . Upon 
pressing and holding the same button, the gas 
switch display is called up. The only result of 
switching gas mixtures in bottom timer mode 
is that the pressure of the newly chosen tank is 
displayed instead of the current one. 

17
12.1.  DIVE VIOLATION INDUCED 
BOTTOM TIMER MODE
The following violations can occur during an 
Air, Nitrox or Trimix dive: 
-  Ascent violation. 
-  Missed deco stop violation.
In case of a violation, Genius will restrict the 
use for 24 hours, and will only allow operation 
in Bottom Timer mode, continuously displaying 
the message LOCKED BY PREVIOUS DIVE.
• 13. TAKING CARE OF GENIUS
13.1.  TECHNICAL INFORMATION
Pressure gauge function
The pressure gauge integrated with the Genius 
dive computer has been tested and CE certified 
by RINA, notified body 0474, located in Genova, 
Italy.
The pressure gauge is a Category III device as 
defined under European Regulation 2016/425, 
and complies with the specifications set out in 
the harmonized European Standard EN250 for 
use with air compliant with Standard EN 12021 
(oxygen content of 21%).
The EC certification process and verification 
of the operating performance of the pressure 
gauge in the Genius dive computer under 
standards EN250 and EN 13949 are understood 
to be applicable to a maximum depth of 50 m 
below the surface. 
The Genius dive computer can be used in cold 
water (water at temperatures below 10°C).
Marking
The instrument markings are located on the 
tank module, and consist of the following:
•  working pressure rating: 300 bar / 4,350 psi;
•  reference standard: EN250;
•  reference marking: CE 0474.
The conformity marking indicates compliance 
with the essential health and safety 
requirements as per European Regulation 
2016/425. The number alongside CE identifies 
RINA, notified body 0474, located in Genova, 
Italy, authorized to inspect the finished product 
under Module D of European Regulation 
2016/425.
Operating altitude: 
-  with decompression – sea level to 
approximately 3700m/12100ft
-  without decompression (gauge mode) – at 
any altitude
Decompression model: Bühlmann ZH-L16C 
with gradient factors (16 tissues)
Depth measurement:
-  Max displayed depth: 150m/492ft
-  Resolution: 0.1m until 99.9m and 1m at 
depth deeper than 100m. Resolution in ft is 
always 1ft
-  Temperature compensation of the 
measurement between -10°C to +50°C / 
14°F to 122°F
-  Accuracy from 0 to 80m/262ft: 1% ±0.2m/1ft
Temperature measurement:
-  Measurement range: -10°C to +50°C / 
14°F to 122°F
-  Resolution: 1°C / 1°F
-  Accuracy: ± 2°C / ± 4°F
Digital compass:
-  resolution: 1°
-  accuracy: ± 1° + 5% of tilt angle (example: at 
50° tilt, accuracy is ±3.5°)
-  tilt angle: up to 80°
-  refresh rate: 1s
Clock: quartz clock, time, date, dive time 
display up to 999minutes
Oxygen concentration: adjustable between 
21% and 99%, ppO2max range between 1.2 and 
1.6bar
Logbook memory: over 1000 hours of dive 
profile at 5-second sampling rate
Operating temperature: -10°C to +50°C / 
14°F to 122°F
Storage temperature: -20 to 70°C / -4 to 
158°F
Display:
-  Diagonal: 2.7”
-  Technology: TFT
-  Resolution: QVGA 320*240
-  Colors: 256000
-  Brightness 420cd/m²
-  Mineral glass
Power supply: 
•  Genius: 
-  lithium-ion rechargeable battery, with 
battery charge indicator
-  operating temperature
-  discharging: from -10 to +50°C / 14 to 
122°F
-  charging: from 0 to 45°C / 32 to 113°F
-  battery duration from one charge: approx 
40 hours of diving. Actual battery duration 
depends on the usage of the high intensity 
backlight and the water temperature
-  lifetime of the battery: approx 500 
charging cycles
Bluetooth:
EU
This device is in compliance with the essential 
requirements and other relevant provisions of 
RED Directive (2014/53/EU).
FCC Warnings/ISED (Canada) Warnings
-  Model: GENIUS FCC ID: 2AIKSGENIUS 
IC:21499-GENIUS
-  This device complies with part 15 of the FCC 
Rules. Operation is subject to the following 
two conditions: 
(1) This device may not cause harmful 
interference, and (2) this device must 
accept any interference received, including 
interference that may cause undesired 
operation.
This equipment has been tested and found 
to comply with the limits for a Class B 
digital device, pursuant to part 15 of the FCC 
Rules. These limits are designed to provide 
reasonable protection against harmful 
interference in a residential installation. 
This equipment generates, uses and can 
radiate radio frequency energy and, if not 
installed and used in accordance with the 
instructions, may cause harmful interference 
to radio communications. However, there is 
no guarantee that interference will not occur 
in a particular installation. If this equipment 
does cause harmful interference to radio or 
television reception, which can be determined 
by turning the equipment off and on, the user 
is encouraged to try to correct the interference 
by one or more of the following measures:
-  Reorient or relocate the receiving antenna.
-  Increase the separation between the 
equipment and receiver.
-  Connect the equipment into an outlet on 
a circuit different from that to which the 
receiver is connected.
-  Consult the dealer or an experienced radio/
TV technician for help.
-  Responsible party’s contact located in 
the United States: MARES USA, Congress 
Corporate Plaza II 902 Clint Moore Road 
Suite 208, 33487 Boca Raton, Florida. 
www.mares.com
-  This device contains license-exempt 
transmitter(s)/receiver(s) that comply 
with Innovation, Science and Economic 
Development Canada’s license exempt 
RSS(s). Operation is subject to the following 
two conditions: (1) This device may not cause 
interference. (2) This device must accept any 
interference, including interference that may 
cause undesired operation of the device.
L’emetteur/recepteur exempt de licence 
contenu dans le present appareil est 
conforme aux CNR d’Innovation, Sciences 
et Developpement economique Canada 
applicables aux appareils radio exempts de 
licence. L’exploitation est autorisee aux deux 
conditions suivantes : (1) L’appareil ne doit 
pas produire de brouillage; (2) L’appareil doit 
accepter tout brouillage radioelectrique subi, 
meme si le brouillage est susceptible d’en 
compromettre le fonctionnement.
ICES-003 Class B Notice -Avis NMB-003 
Classe B : 
This Class B digital device complies with 
Canadian ICES-003
Cet appareil numerique classe B est conforme 
à la norme Canadien NMB-003.
CAN ICES-3(B) /NMB-3(*)
-  Responsible party’s contact located in the 
Canada: Head Canada Inc, 935A Southgate 
Dr, Guelph on N1L 0B9 Ontario, Canada, 
www.head.com.
-  Changes or modifications not expressly 
approved by the party responsible for 
compliance could void the user’s authority to 
operate the equipment.
Others
This product uses a module which obtained 
a certification of construction type issued by 
Japan Radio Act.
CAN ICES-3(B) /NMB-3(B) 

GENIUS Dive Computer
18
13.2.  MAINTENANCE
The tank pressure gauge and the parts of this 
product used to measure tank pressure should 
be serviced by an authorized Mares dealer 
every other year or after 200 dives (whichever 
comes first). In addition, the depth accuracy 
should be verified every two years. Aside from 
that, Genius is virtually maintenance free. All 
you need to do is rinse it carefully with fresh 
water after each dive (avoid any chemical 
products) and charge the battery when needed. 
To avoid possible problems with your Genius, 
the following recommendations will help 
assure years of trouble free service:
-  avoid dropping or jarring your Genius;
-  do not expose Genius to intense, direct 
sunlight;
-  do not store Genius in a sealed container, 
always ensure free ventilation.
NOTE
If you notice signs of moisture on the 
inner wall of the mineral glass, take your 
Genius immediately to an authorized Mares 
service center. 
 WARNING
The mineral glass is not exempt from 
scratches resulting from improper use.
 WARNING
Do not blow compressed air onto Genius, 
because it could damage the pressure 
sensor area.
13.2.1.  REPLACING THE BATTERY IN GENIUS
Genius uses a rechargeable battery, and it may 
be necessary to replace it after approximately 
500charging cycles. The battery should only 
be replaced in a center authorized by Mares. 
Mares declines all responsibility for any 
damage caused by replacing the battery.
NOTE
Dispose of the old battery properly. 
Mares adopts a policy of respect for 
the environment, and urges use of the 
appropriate separated waste collection 
services.
• 14. WARRANTY
Mares products are guaranteed for a period of 
two years subject to the following limitations 
and conditions:
The warranty is non-transferable and applies 
strictly to the original purchaser.
Mares products are warranted free from 
defects in materials and workmanship: 
components that, upon technical inspection, 
are found to be defective, will be replaced free 
of charge.
Mares S.p.A. declines all responsibility 
for accidents of any kind that result from 
tampering or incorrect use of its products.
Any products returned for overhaul or repairs 
under warranty, or for any other reason, must 
be forwarded exclusively via the vendor and 
accompanied with a proof of purchase slip. 
Products travel at the risk of the sender.
14.1.  WARRANTY EXCLUSIONS
Damage caused by water seepage resulting 
from improper use (e.g. dirty seal, battery 
compartment closed incorrectly, etc.).
Rupture or scratching of the case, glass or 
strap as a result of violent impact or blows.
Damage resulting from excessive exposure to 
elevated or low temperatures.
Damage caused by the use of compressed air 
to clean the dive computer. 
14.2.  HOW TO FIND THE PRODUCT 
SERIAL NUMBER AND 
ELECTRONIC ID
The serial number is laser-engraved on 
the back side of Genius, in front of the front 
attachment point of the strap.
To see the electronic ID, enter the INFO menu.
Both serial number and electronic ID can be 
found on the warranty card inside the box and 
also on the label outside the box.
• 15. DISPOSAL OF THE DEVICE
Dispose of this device as electronic waste. 
Donot throw it away with regular rubbish. 
If you prefer, you can return the device to your 
local Mares dealer. 

19

GENIUS Dive Computer
20
• FIGURE

21
• FIGURE

Mares S.p.A. - Salita Bonsen, 4 - 16035 RAPALLO - ITALY - Tel. +39 01852011 - Fax +39 0185201470
www.mares.com
2016/425: www.mares.com/declarations
code 44201490 - 0.000- 09/18 - Artbook 14884/18