Computer question...O2 adjustment..turning on

Greetings:

I have an Aeris Savant and Genesis React computer and dive with both.

1. When you turn your computer on FOR THE FIRST TIME at the beginning of a dive trip should you be in the water floating on surface or is it OK to turn it on FOR THE FIRST TIME FOR THE FIRST DIVE while you are still on the boat deck? I was wondering if you turned it on while on the boat if it would mess up your computer's depth calculation since it would not be calbrated to the surface level of the water? Does it make any difference?

2. If you are going to do multiple nitrox dives with a FO2 32%--do you typically
leave the F02 ON and re-set the O2 percentage every dive, or just turn OFF the default so the computer remains at the original 32% setting for the duration of the dive trip? Again, can this be done on the boat or should you do it on water surface?

3. I am pretty good at setting these computers, but in the past I programed the settings while floating on the surface of the water. After turning the FO2 default off on both computers, then setting the O2 percentage--it seems like I spend too much time fumbling with these computers on the surface and was wondering if I could avoid all that by just pre-setting them while still on the boat? Would that cause them to give inaccurate readings?

Thanks,

Vandy

1) no... turning it on while on the boat or above the surface is just fine.

2) Leave the FO2 on... it may not even reset between dives.

3) Presetting on the boat is optimal.

Following activation, the computer will shut off and revert back to factory default FO2 settings following 2 hours without conducting a dive - so, as long as you keep that in mind and give yourself time for travel out to the dive site and into (under the water) setting your computer up prior to getting into the water is going to be much easier for you.

With the FO2 50% Default ON - you must change your mix between dives, otherwise the computer will default to an impossible mix of 50% O2 and 79% Nitrogen - covering you for whatever gas mix you may be using. Another thing to keep in mind, is that the computer defaults to this setting following 10 minutes on the surface. If that occurs during a dive for any reason, the default 50/79 mix will be active.

I typically recommend that the setting is set "OFF", provided you confirm and reprogram your FO2 if necessary between dives.