Computer Usage

[dwwest101]

I recently purchased an Aeris Atmos 2 dive comp. While browsing through different dive shops seeing what each had to offer one of the guys working in one of the shops gave me some advice. He told me to use the Nitrox setting and set the o2 at 21 rather than use the air mode. I am not Nitrox certified yet, but maybe someday. I have been watching this board for a while and everyone seems to make good points. What do some of the more expierenced divers think about using the comp this way? Actually this was the first and only time I have ever been in that particular shop so I dont know this guy from Adam. I am still getting used to the comp and have read the manual about 20 times and almost wore the first set of batteries out and it wont be in the water until July when I go to Cozumel. BTW...Thanks for any points you make on this.

 

[Quarrior]

I recently purchased an Aeris Atmos 2 dive comp. While browsing through different dive shops seeing what each had to offer one of the guys working in one of the shops gave me some advice. He told me to use the Nitrox setting and set the o2 at 21 rather than use the air mode. I am not Nitrox certified yet, but maybe someday. I have been watching this board for a while and everyone seems to make good points. What do some of the more expierenced divers think about using the comp this way? Actually this was the first and only time I have ever been in that particular shop so I dont know this guy from Adam. I am still getting used to the comp and have read the manual about 20 times and almost wore the first set of batteries out and it wont be in the water until July when I go to Cozumel. BTW...Thanks for any points you make on this.

Using it in 21% mode Nitrox is the same as air. Advantage is that if/when you get Nitrox certified, you only have to adjust the oxygen % rather than switching from Air to Nitrox. Really helpful when diving multiple dives with different mixes. This is what I learned in Nitrox class, btw.

Why are you waiting so long to get wet? Is there no water where you live?

Brian

 

[H2Andy]

well... did he tell you why? did you ask?

i have the Atmos 2 as well, but haven't really noticed if there is a difference between
air mode and O2 at 21% (i.e. air). i suspect there wouldn't be?

anyone know?

[edit] ooops slow typing tonight

 

[Sideband]

I'm definitly not one of the more experienced divers, but I have the same computer. When we were doing a nitrox checkout dive the instructor suggested the same thing. He said that once you do an air dive that you can't change the settings to enriched air until the next day. If you set it for EANx 21 then you can dive air one dive then switch to EANx 32 or 36 later that day with no problems. I don't see a benefit for someone that can only dive on air but if EANx is a possibility then it makes perfect sense to me.
Anyone else hear this or have other opinions?

Joe

 

[AtomicWalrus]

I can't speak for Aeris computers, but my Suunto won't allow changes between air & nitrox until you've desaturated. Instead, I just leave my computer in nitrox and set it to 21% when I'm diving air. The display is subtly different between the 2 modes, and it's not a bad idea to leave the computer in the display you're used to. That just reduces any problems you're going to have if you're narc'd at depth. For my computer, the "consumed bottom time" bar graph of the air mode turns into an oxygen limit fraction bar graph for the nitrox mode.

I'm definitly not one of the more experienced divers, but I have the same computer. When we were doing a nitrox checkout dive the instructor suggested the same thing. He said that once you do an air dive that you can't change the settings to enriched air until the next day. If you set it for EANx 21 then you can dive air one dive then switch to EANx 32 or 36 later that day with no problems. I don't see a benefit for someone that can only dive on air but if EANx is a possibility then it makes perfect sense to me.
Anyone else hear this or have other opinions?

Joe

 

[wedivebc]

well... did he tell you why? did you ask?

i have the Atmos 2 as well, but haven't really noticed if there is a difference between
air mode and O2 at 21% (i.e. air). i suspect there wouldn't be?

anyone know?

[edit] ooops slow typing tonight

I think the only difference is you don't get the po2 displayed on the second screen (when you push the yellow button) in air mode. Otherwise it should be the same.

H2Andy, it's ok about the slow typing I don't read too fast anyway.

 

[Mark Vlahos]

Hi,

It is really quite simple, if you are not trained on Nitrox... Just leave it set on AIR. There will be fewer things to worry about, and you can dive safely with the computer.

If you later decide to get trained in the use of Nitrox as a breathing gas (in my opinion this training is a good idea) then, and only then, change the computer to use 21% instead of AIR.

If you are not trained in Nitrox you could mistakenly change the breating gas mixture without understanding the ramifications of the mistake. This error could be dangerous. The danger is to stay at depth too long for air. If you are not trained in the use of Nitrox I do not see any advantage to switching your computer to 21%, but I do see a disadvantage.

In the future if you get trained in Nitrox you will then understand what the manual is saying about setting the mixture and it will make more sense.

Dive safe, dive often.

Mark Vlahos

 

[Chivas]

Please read Mark's post very carefully. Using the Nitrox Mode when using Air certainly works, but it adds another potentially dangerous variable if not set correctly.

 

[scubatoys]

When we dive on air - we have to worry about our nitrogen intake - when we dive on Nitrox, we also need to worry about oxygen intake. If the computer is set for nitrox, it will track your O2 time as well. So after you do a nitrox dive with the aeris - anywhere from 21-50%, if won't let you switch back to air for the next dive - because then it won't continue tracking O2 time... So it forces you to set it back it 21 instead of the actual "AIR" setting. Then the O2 clock keeps running.

Now the main problem is another feature called "FO2 50" which can be toggled off or on in the Set 2 area of the computer. If that is set "ON", which is the factory default, after you do a dive on nitrox, you must reset the computer on the next dive - even if diving the same mix. Otherwise, it will assume you are on Air for your deco time, but on a 50 mix for your max depth. It does this as a safety setting to make you reset your nitrox level each time - or else it will assume the worst possible case, just to try to keep you safe. This will limit you to about 60 feet and it will start beeping at you and freaking out.

So over all - keep it on air if diving air... when you take a nitrox class and are using nitrox - then set it for nitrox.

 

[dwwest101]

Thanks for all the replies. This was exactly why I asked other divers rather than relying on on persons advice. So I will set the computer to air and dive like that until I get my Nitrox certification.