21% Nitrox

[Ontwreckdiver]

Good for you. I have been diving my Cobra for over 20 years and it has never missed a beat. I would buy it again if I had a do over.

 

[dmaziuk]

And this seems to present the question: why does a nitrox capable computer even have an "air" mode?

Could be they had an air-only model and decided it's cheaper to keep it and tackle on nitrox as a completely independent subsystem. I've seen it happen with other software but I'm having a real hard time beleiving someone would do that in this case: "nitrox" mode is a proper superset of "air" and I can't think of any reason to do that except a complete total absence of clue. (Edit: @EFX: battery drain from an extra segment on a TN display is somewhere between infinitesimal and negligible.)

FWIW on mine "nitrox" O2% is settable between 22 and 50 and O2 toxicity is tracked all the time, regardless of the "mode".

 

[Belzelbub]

Which really sucks on a liveaboard, but better than reverting back to 79% N2 and 50% O2 like they used to. That’s the whole reason I got rid of all of my suuntos

It shouldn’t really be that hard to check and change your gas mix settings. If it is, the UI needs work. I would agree that reverting to normoxic Nitrox after a certain period isn’t necessary, and shows a lack of faith in the users. Which, to some extent, I get, but it’s not the responsibility of the computer manufacturer to babysit its customers. It’s their responsibility to make a computer that is easy to change those settings that are frequently changed.

Reverting to 21% without calculating as 79/50 could be a bit dangerous from a MOD perspective assuming the diver is as irresponsible as the manufacturer seems to suspect.

FWIW, I previously used a computer that would revert to 79/50 at some point. I can’t recall what that time limit was, though. I also never experienced this on a dive as I confirmed/changed the mix settings before each dive.

 

[Easdem]

I typically only dive Nitrox when doing 3 or more in a day. Then if I am going back to 2 dives a day I'll just use air.

However I will dive Nitrox one day then dive 2 tanks air daily for a week but have to set for Nitrox at 21% not set for air.

Air is 21%Eanx. Wether it says Air or 21% is irrelevant. Most computers I have owned only display the O2% you are using.