Suunto Gekko nitrox setting when using air

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chironomidkraut

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Location
Alberta, Canada
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A couple people on here say the put their GEKKO in nitrox mode even when using just AIR! I was just wondering some advantages or dis advantages of doing this??:eyebrow:
 
I think they do it the other way around, use it on the air setting when using nitrox. It is just giving you a better margin or safety.

The reasoning is that with nitrox you are breathing less nitrogen and more oxygen, and if you leave the computer in air mode it will let bring you up sooner since air is 21% oxygen and contains 79% of nitrogen, pollutants, anything else that may be in there as well. So with that is mind if you were diving 32% nitrox(32% oxygen) you would have less nitrogen built up in your body than if you were diving air(21% oxygen).

But then again don't quote me to this, I am new to the nitrox side or diving, and am still working on my understanding of it.
 
If all you use is air there is no advantage. However, if you have a nitrox ticket ,it lets you dive air and or nitrox on the same dive trip.

You can't switch modes unless the computer is 'clean'. So if you started on air and then wanted to do a nitrox dive, you couldn't switch to that mode for 24 hours. Since the computer defaults to 21% in nitrox mode you will never notice the difference if you dive air and have it in nitrox mode. One difference about nitrox mode is it will track O2 exposure while you dive air ;-) not much use unless you are a little deeper than you really should be.
 
The issue is that there are two separate configuration settings, and they tend to get confused.

There is nitrox mode, which is one of the two [ Air, Nitrox ].
The Gekko doesn't have a Gauge mode as I understand it; its big brothers the Vyper and Cobra have three modes [ Air, Nitrox, Gauge ]. This mode selection is a persistent setting, done through the "Set Preferences" screen, similar to selecting one of [ Metric, Imperial ] for units display. The computers ship in Air mode.

Once you have set the preference to nitrox mode, you can set the %O2 and PO2 in the Nitrox screen under "Set Dive" screen. If in Air (or Gauge) mode, the Nitrox screen is hidden. The Nitrox %O2 will automatically reset to 21% (air) after the no-fly time counts down to zero at the end of a dive series. The Nitrox mode will not change until you manually change it back to Air (or Gauge).

The Suunto manual actually recommends that if you are certified for Nitrox, that you change the mode to Nitrox permanently, and just leave the %O2 at 21% when diving air. The reason is that if you start a dive series with the computer in Air mode, then decide you'd like to start diving nitrox, you won't be able to change the mode to Nitrox until the no-fly time expires (end of dive series).

The reason for that is that in Air mode, the computer is not tracking your O2 exposure, so they have to wait until you're all cleared out to change modes, otherwise there would be a theoretical risk of pulmonary O2 toxicity that the computer couldn't be aware of if you really went wild on the nitrox. In Nitrox mode, even with 21% O2, the computer is tracking your pulmonary oxygen toxicity load, so if you start diving at 21% (Air) and switch on later dives to say EANx 32 or 40, the computer can advise about O2 toxicity.
 
I used a Gekko for a short time and it was so conservative I set it on 24% nitrox all the time. I am not recommending this but I felt comfortable doing it. Never got bent so it worked for me. Perhaps your friend did the same.
 
...change the mode to Nitrox permanently, and just leave the %O2 at 21% when diving air. The reason is that if you start a dive series with the computer in Air mode, then decide you'd like to start diving nitrox, you won't be able to change the mode to Nitrox until the no-fly time expires (end of dive series)...

This is the answer to the OP (same as what hdugan said)
 
so when i switch the comp to nitrox mode, it starts out at 21% oxygen right? and how deep would i have to go to get the full benifit of the o2 exposure, vs air mode
 
so when i switch the comp to nitrox mode, it starts out at 21% oxygen right?

Yes, then you can adjust it as required (if you're diving nitrox). Or if you're on air then just leave it at 21%

and how deep would i have to go to get the full benifit of the o2 exposure, vs air mode

21% nitrox and air are the same thing. O2 exposure will be the same. Depth isn't relevant. Not sure what you're asking

From your profile I gather you're not nitrox certified, so if you won't be diving nitrox there isn't any point to using nitrox mode instead of air; just leave it alone until you get your nitrox cert
 
If you're not Nitrox certified yet, there is no point in putting your computer in Nitrox mode. But for people using the Gekko and similar Suunto computers for Nitrox, there are 2 things that trip up many at first-

1) starting a dive series in Air mode when you want to dive Nitrox, because once you've done that you're stuck in Air mode until the computer clears. This is why most people who use Nitrox at all learn to leave a Gekko in Nitrox mode, and simply have the O2 percentage set at 21% when diving air. As long as you are at least in Nitrox mode, if you forget to set or check the O2 percentage before a dive you can at least change it for the next dive.

2) not being aware the Gekko will reset itself to 21% O2 (equivalent to regular air) after certain periods of time, so you should always check before a dive.


If you want to be conservative and dive Nitrox on air profiles, you could also leave the computer set to 21% O2, or something in between. The drawback is it won't be tracking your O2 exposure properly, although O2 is rarely the limiting factor doing the usual 32% recreational diving thing. And the Gekko is already a fairly conservative computer anyway.
 
so when i switch the comp to nitrox mode, it starts out at 21% oxygen right? and how deep would i have to go to get the full benifit of the o2 exposure, vs air mode

At work at the moment and don't have info handy, but i think it is 218fsw when PO2 reaches 1.6ATA at 21% O2. This is when you run the risk of oxygen toxicity.

Don't go there!!!!!
 
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