Air to Nitrox in same trip

[ReneeDr]

Ok, so I do have an Oceanic computer, and It appears that I can set It to 21 percent and it will calculate nitrogen and oxygen exposure both. So as I see it that will not be a problem.

Or will that mess up my "remaining air time computations" that my computer calculates automatically?

 

[deepstops]

Ok, so I do have an Oceanic computer, and It appears that I can set It to 21 percent and it will calculate nitrogen and oxygen exposure both. So as I see it that will not be a problem.

Or will that mess up my "remaining air time computations" that my computer calculates automatically?

If your plan is to dive air followed by nitrox within a 24 hour period, set your computer to 21% nitrox and then set it to the correct % of nitrox when you switch to nitrox. This way you will get correct nitrogen and oxygen loading calculations for all your dives.

 

[ReneeDr]

Ok, thanks!

 

[iztok]

Incorrect statement for at least Suunto, Uwatec, and Oceanic. These three (the major three IMO) will not permit switching to nitrox after doing an "air" dive and the reason is because when they are set to "air" (as opposed to 21% nitrox), they do not calculate O2 exposure.

Suunto D9 manual quote:

It is not possible to change between Air, Nitrox and Gauge modes before the instrument
has counted down the no-fl ying time.
There is one exception to this: You can change from Air to Nitrox mode even during
the no-fl ying time. When planning both air and nitrox dives during the same dive series,
you should set the instrument in Nitrox mode and modify the gas mix accordingly.

Oceanic Veo 180nx:

When set with F)2 valie of "Air", the Veo 180nx will perform calculations the same as if FO2 were set for 21% oxygen, internally accounting for oxygen loading for subsequent Nitrox dives.

So please stop spreading misinformation.

Suunto D9 and Oceanic Veo 180Nx can switch from Air to Nitrox but not the other way around between the dives. (One would have to wait enough time to switch back to Air if dive is made on Nitrox.)

 

[iztok]

If your plan is to dive air followed by nitrox within a 24 hour period, set your computer to 21% nitrox and then set it to the correct % of nitrox when you switch to nitrox. This way you will get correct nitrogen and oxygen loading calculations for all your dives.

You REALLY need to read computer manual. Suunto and Oceanic (at least) will calculate oxygen loading when in "Air" setting as well just not display it to the user. That is why it is possible to switch from "Air" to "Nitrox" mode between dives but not other way around.

 

[Scared Silly]

It is actually the other way around. Once you dive nitrox you can not switch to air but you can set it up to 21% mixture

Thanks I could not remember which way it will not switch as I just leave mine in Nitrox mode all the time - regardless though it is something folks should now about and many do not.