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Aeris A300 CS Dive Computer That Favored by Serious Divers

Aeris A300 CS Dive Computer That Favored by Serious Divers

Aeris A300 CS OLED combines exceptional quality and a full range of innovative features to meet the needs of the most demanding divers! Colour high-resolution display put dive data on a new quality level. Dual Algorithm feature allows divers to choose between conservative and liberal diving. Wireless air integration with up to 4 TMTs gives you an advantage of using 4 gas mixes and precisely track your air consumption in easy to read format.

General Information
User Interface
Your Review



Aeris A300 CS OLED is an advanced dive computer with switch function between 4 gas mixtures and the possibility of wireless air integration. It is equipped with integrated electronic compass, colour display, Dual Algorithm and 4 dive modes. It is multifunctional instrument that provides full information about decompression. Detailed digital information is duplicated by intuitive colour-coded numbers. Blue and green colours correspond to the concept of security, red digits warn the diver, orange - demand attention.

When compass is activated - graphic image occupies most of the screen, and the use of different colours in the compass makes it incredibly easy to read information.


Video Introduction to Aeris A300 CS OLED. Unable to watch this video? Watch it on Youtube


Another outstanding feature of Aeris A300 CS OLED - integrated Bluetooth module. It allows interconnection with PC/Mac by using wireless technology avoiding often frustration of the weak connection when using cables.


Aeris A300 CS OLED functions

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Benefits of using Aeris A300 CS OLED dive computer

  • you will get a multifunctional dive computer for any dive occasion (not for Trimix);
  • you will learn this dive computer very quick and be ready diving in no time, thanx to intuitive interface and great user manuals;
  • you will be able to use wireless air integration for up to 4 tanks;
  • you will enjoy high contrast coloure display with intuitive colour-coded digits;
  • you will be able to replace a battery by yourself;
  • you will be able to connect with ease to PC/Mac using Bluetooth technology;
  • you will move along with the latest innovations in dive gear design technologies (on the moment of writing this review!)







User Interface
3 buttons
Dive Modes
Air, Nitrox, GAUGE, FREEdive
Integrated Digital Compass
Dual Algorithm
Pelagic DSAT/Z+
Number of Gas Mixes
Air, 21-100%
1.0 - 1.6 ATA
Air Integration
Safety Stop (SS)
Deep Stop (DS)
Conservative Factor
Altitude adjustment
Gas Switching
Dive Planner
9 - 57 meters
Logbook Capacity
24 most recent dives
Max Operational Depth
100 meters
Backlight duration
Auto Dim/10-100%
Sampling Rate
2/15/30/60 sec
User Replaceable Battery
Data retention
PC/Mac Interface
2 years










Aeris A300 CS OLED has 3 buttons - two of them located in front and third is on the right side. They are quite big, easy accessible and convenient to press.

Dive computer has colour display with intuitive colour-coded digits - blue and green colours correspond to the safety conditions, red digits warn the diver, orange - demand attention.

Display is devided into 3 setions, digits are big and clearly seen underwater in any dive conditions. Auto Dim function is very convenient option. By enabling it diver will not only make automatic brightness adjustment according to environment, but also save the battery power.
Display has main and alternative screens to provide the user with information available in certain moment whether on surface or under water.


Aeris A300 CS OLED dive computer


A300 CS dive computer has 2 bar graphs:

  1. Tissue Loading Bar Graph from the left side - represents nitrogen loading and shows you no-decompression and decompression status: when you go deeper and dive time increases, segments will be added to TLBG, and when you ascend – amount of segments decreases therefore giving you more time to stay underwater;
  2. Ascent Rate Bar Graph (VARI) from the right - it plays the role of ascent speedometer, it has 3 zones: green, considered to be normal rate of ascent, yellow – that’s a caution zone, and red – is too fast rate of ascent







Aeris A300 CS OLED has very intuitive set of menus. From Home Menu on surface diver may set dive mode and all desirable parameters. Also you may turn integrated Compass mode from Home Menu.


Aeris A300 CS OLED setup

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Also I used Dive Planner, which is the main purpose - planning all consecutive dives. And it does it perfectly by displaying NO-DECO depths and times according to residual nitrogen from the previous dives, FO2 set point(s), altitude and personal conservative factor adjustments. It shows NO-DECO limits in depth range 9-57 meters. But bear in mind that all calculations are made for Gas #1 only!

Also it is a good idea to fill in "MY INFO" section from HOME MENU from the very beginning of using Aeris A300 CS OLED dive computer. You could do this from PC/Mac interface software.







Aeris A300 CS OLED: Diving With Air & Nitrox

Aeris A300 CS OLED activates selected dive mode when it senses depth of approximately 1.5 meters. Dive computer starts monitoring NO-DECO Dive Time Remaining (NDC)/O2 Time Remaining (OTR) and Air Time Remaining (ATR). NDC is the time that represents our safe conditions underwater before hitting DECO. OTR is the time that corresponds to the O2 accumulation during this dive and previous dives. If safe time remaining before getting O2 limit (max allowed 300 OTU) becomes less than NDC - all calculations got controlled by O2 and OTR is displayed as Dive Time Remaining (DTR) instead of NDC.

When TMTs are correctly paired I saw active tank pressure shown at the lower left corner of display. It is colour-coded and easy readable. Also at the low right area of the display computer shows Air Time Remaining in minutes. If there are no TMTs - dive computer displays gas in use and SPG graphic.

During this time I could adjust brightness, access NO-DECO ALT display, preview Deep Stop (DS) display (if DS activated), turn on Compass, or record an Earmark.


Aeris A300 CS OLED No-DECO diving

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Upon reaching certain conditions dive computer gave me Safety Stop prompt with dive data regarding to this situation displayed - SS icon, SS depth and Timer. During setup process it is possible to set Safety Stop to ON/OFF or ajust Timer for 3/5 min and Depth 3/4/5/6 meters.

For extra safety I set Deep Stop (DS) to ON, because I was sure to dive deeper than 24 meters. So in certain moment I had DS icon triggered on Aeris A300 CS OLED display. When I saw that - I could preview the DS screen from NO DECO ALT display by pressing A-button for less than 2 sec.

Aeris dive computer has very nice colour-coded VARI - ascent rate indicator: just stay in green-coloured zone and you will be fine!

As A300 CS is capable of handling 4 Nitrox gas mixes - I definitely wanted to check switching gas feature. With TMTs installed it easy to do. From Dive Main screen by pressing M-button I could access Gas Switching Display with all mixes available displayed. Select your next gas mix and computer will start searching for TMT and switching to that air-tank.


Monitoring High PO2 and High O2 are the standard functions of any dive computer and this one has all means to warn the diver about those mentioned conditions. High PO2 has two levels: Warning & Alarm. They are colour-coded: for Warning level dive computer display notation in orange, if oxygen partial pressure increases to PO2 alarm level - A300 CS flash all in red colours with notation: GO UP and UP-arrows.

This dive computer has another great feature - integrated digital compass. I could call it any time whether on surface or underwater. I don't need to mention here that to use it properly - you need it get calibrated and set the correct declination.


If we exceed our No-Decompression Limits (NDLs), Aeris A300 CS OLED activates DECO mode. Upon entry into this mode you will hear an audio, DECO ENTRY notation will flash in red and applicable dive data will be displayed. From this moment all calculations will be made regarding to Decompression mode. Dive computer manages DECO Stops perfectly - all dive data is very self-explanatory and colour-coded. So I need to follow computer instructions to stay on the safe side.


Aeris A300 CS OLED DECO diving

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As a standard set of functions for every dive computer - A300 CS has number of DECO Violations that may occur during diving:

  1. Conditional Violation (CV);
  2. Delayed Violations (DV): ## 1/2/3;
  3. Violation GAUGE mode


They might happen if he/she ascends shallower and stays for some time above the displayed DECO Stop depth, or diver may descend deeper than maximum operational depth (MOD), or decompression stop requires more than 21 m deep – in this case dive computer activates appropriate Violation mode and manages it to help us safely perform decompression and safely ascend.


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Aeris A300 CS OLED: Diving In GAUGE Mode

Aeris A300 CS OLED may be used as a GAUGE. It doesn’t perform any calculations of nitrogen and oxygen loading and decompression conditions. Dive computer can be used as a depth gauge and timer only. As with other computers, after diving with this one in GAUGE mode you need to wait at least 24 hours before you may use it for diving with Air or Nitrox.

GAUGE mode has its own number of parameters to set in Alarms/TMTs/Utilities menus. And available parameters for GAUGE mode are the same as for NORM mode:

  1. Set TMTs Menu - entering linking TMTs codes (they are TMTs serial numbers)
  2. Set Alarms Menu (NORM)
    1. Audible: OFF/ON;
    2. Depth alarm: OFF/10-100 meters;
    3. Elapsed Dive Time (EDT) alarm: OFF/10-180 min;
    4. TURN alarm (1st TMT): OFF/1000-3000 PSI;
    5. END alarm: 300-1500 PSI
  3. Set Utilities Menu (NORM)
    1. water: fresh/sea;
    2. units;
    3. sampling rate: 2/15/30/60 sec

After we checked on preview screen that everything is correct - we are ready to test computer in GAUGE mode underwater.

From GAUGE Dive Main display I could call compass or adjust brightness.

GAUGE Dive Main display following:

  • current depth;
  • Elapsed Dive Time (EDT);
  • Air Time Remaining (ATR);
  • TMT in use;
  • pressure of the tank in use;
  • VARI (if ascending)

To access GAUGE ALT display - I pressed A-button shortly. GAUGE ALT display looks like that:

  • Run Time;
  • max depth;
  • time;
  • temperature


It is possible to make a Delayed Violation 3 in GAUGE mode. It happend if diver goes below the max operational depth - 100 meters. So there are three dashes on display instead of current depth, and a notation in red colour - GO UP TOO DEEP with red UP-arrows. Also values of the pressure of the tank in use, ATR displayed, and VARI if ascending.


Aeris A300 CS OLED: FREEdiving

In FREEdive mode A300 CS OLED calculates nitrogen loading according to default FO2 of Air and the residual amount that you may have left between diving with Air, Nitrox and this freediving session.

Special settings and alarms for FREEdive mode can be accessed and set from Free menu. We may set following functions and alarms:

  1. Countdown Timer;
  2. water type: fresh/sea;
  3. units;
  4. Repeating Time Interval (RTI) alarm: OFF/ON (if ON - alarm activates every 30 sec);
  5. Freedive Depth alarms – 3 depth alarms that can be set at progressively deeper depths at a range 10 – 100 meters in 1 meter increments

RTI is made as a part of Elapsed Dive Time in this computer, so when set to ON and after, for example, 4 activations - we have our EDT of 2 minutes.

FREEdive MAIN display consists of not too much information that is very easy to read:

  • TLBG (if you have any level of residual nitrogen from previous dives);
  • Elapsed Dive Time (EDT);
  • current depth;
  • temperature

To access FREEdive ALT display - press A-button shortly to view:

  • Countdown Timer (CDT) status;
  • NO-DECO Time (NDC);
  • max depth;
  • time and date


During freediving you will get all freedive alarms that you set previously - RTI alarm will sound every 30 seconds elapsed, Depth alarms will remind you about set points of the depths reached, Countdown Timer alarm will beep on you when time decreases to 'zero'.

Also you may have another alarm - TLBG alarm. This one activates when nitrogen remained from previous dives and current nitrogen loading reaches the Caution zone (9 segments). It may even happen when nitrogen level will increase to Decompression condition. In this scenario computer will activate Violation mode for 24 hours, which means that diver must stay on surface for 24 hours without any diving activities.


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Aeris A300 CS OLED activates Post Dive Surface Mode upon ascent to 0.6 meters for 1 second. User access to other surface modes/displays blocked until 10 minutes of transition period elapsed. From this point I could access NORM/Home menues and Compass mode.


 Aeris A300 CS OLED post-dive modes

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Modes that I was interested in at this moment listed below:

  1. Time To Fly Countdown Timer;
  2. Time To Desaturate;
  3. CLEAR Ni-O2 calculations - may be useful for sharing dive computer;
  4. Dive Planner (9-57 meters) – this function allowed me planning next dive sessions and seeing for how long I could stay underwater safely and at what depth, according to my current nitrogen accumulation, oxygen toxicity, altitude, and conservative factor;
  5. Log modes: NORM/GAUGE/FREEdive - displays dive data for the most recent 24 dives (NORM/GAUGE) or 99 dives for FREEdive;
  6. History mode;
  7. Set mode - enter and edit all Aeris A300 CS settings;
  8. Upload/Download data to PC/Mac - interconnect dive computer with PC/Mac using bluetooth or USB cable







Aeris A300 CS OLED: What Divers say


  • great colour display visibility in any light conditions;
  • gives a lot of information underwater and on surface;
  • easy and comfortable switching procedure between gas mixes;
  • lots of functions and easy to set;
  • reccommended dive computer as for advanced divers and novice divers who are serious about their diving career;
  • smooth bluetooth connection with my PC after upgrading drivers;
  • very stylish and solid built dive computer


We have only positive emotions while using and diving with Aeris A300 CS OLED. It is really something very new from Aeris! It inherited only the best things from all range of Aeris dive computers and got lots of new features and one of them colour display! Display is crystal clear and all messages are easy to read even in muddy water. I reckon you will love Auto Dim feature - it allows auto-adjustment of the brightness of the display, therefore saving battery power. I loved large display with all essential data shown, and extra info was easy to call up.

User interface is structured comfortable with an easy to access and press buttons: if you have previous experience with dive computers - you won't have a single problem with it! Novice divers are advised to work on user manual thoroughly to feel themselves comfortable underwater with this Aeris dive computer.

Switching gases was easy and intuitive to perform. Aeris A300 CS OLED has 2 types of different Gas Swith Menu displays for switching gases in NORM and GAUGE modes. In NORM mode dive computer displays each gas with FO2 and expected PO2, but in GAUGE mode dive computer shows only number of transmitters (if activated).

Another great addition to this Aeris dive computer - integrated digital compass. For underwater navigation - it is the best! Before using it I had to calibrate it and all went smoothly, just followed procedures from user manuals.

I liked that this dive computer is capable of being customized for different diving situations and it is a big benefit for those guys who want to dive different scenarios, like air and nitrox, or gauge and freediving, and at the same time it provides us with everithing to keep us safe!


Aeris A300 CS OLED dive computerAeris A300 CS OLED
Dive-Computer-Wizard Rating
golden star golden star golden star golden star golden star


I can say that Aeris A300 CS OLED is a perfect addition and logical progression in high-tech Aeris dive computers family and with its crystal clear colour display, Dual Algorithm, 4 dive modes, 4 gas mixes, integrated digital compass, and wireless air integration gives us opportunity to extend our underwater experiences to greater limits!
If you are serious about diving and love high-tech stuff, if your budget allows you to spend quite a bit of money and withstand that "financial burden" - Aeris A300 CS OLED is definitely for you!



Add comment
Robin, 21 June 2014 06:47
Aeris Combined All The Great Functions In One Body

That's my second Aeris dive computer, after Aeris Epic. I decided to get A300 CS OLED at the moment when I saw it' been announced!

I don't have enough words to describe all the pleasure I had diving with it: great display visibility, colour-coded digits, bar graphs and symbols, convenient user interface, steady wireless (I have only one TMT at this moment), very nice compass, easy to set up...

Even my mistress wanted to grab it from me and add Aeris A300 CS to her dive gear, but I'm still standing!

PC software needs some work to make it perfect as dive computer itself, but it does its job.

I logged almost 50 dives on it, so I would definitely recommend Aeris A300 CS OLED to every diver who is serious about diving, and not just want to have a flashing toy on their wrist!

NickO, 5 June 2014 10:21
Pricey, But Worth Every Cent If You Can Afford It!

This is a fantastic dive computer. The colour display makes it easy to read even in poor light conditions. Set up and dive functions are extremely user friendly and whole system works like a charm with wireless transmitter. Color HD screen is great and I could see everything on the screen from my depths and compass.

A300 CS is very functional, has all the possible features and settings that can be found on a dive computer these days!

It is comfortable on the wrist, and quite easy to navigate - getting from screen to screen to retrieve dive data, and edit the options!
This dive computer is not for those who want something simple and flashy, but for those serious divers who needs tons of great features and ready to pay for them. And if you are one of them - then this computer is a great choice. Just be prepared to spend a little time figuring out how to use it, and of course, get ready to spend more money!

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