air vs. bottom time on Darwin? NEWBIE

[lisaleese]

I have a question about which way to set up my Darwin. I know it has "Nitrox" - which I won't touch for a LONG time, "air" and "bottom time." I am runnning on the "bottom time" setting. If I set it for "air," does that mean I'm calculating my NDL by the air remaining in my tank and breathing rate, vs actual time underwater?

Thank you for your patience!

 

[Boogie711]

It has no idea what your breathing rate is, and breathing rate has no impact on NDL times regardless.

If you were to get into Nitrox settings, your NDL times would be different as you were diving.

Incidentally, you should get identical NDL times with "Air" as you would with a 21% Nitrox setting.

 

[lisaleese]

Is there, then, any benefit to using the bottom time setting vs the air setting?

 

[Boogie711]

In bottom time mode, all it will tell you is your depth and time underwater.

In "Air" mode, it functions like a computer, calculating your NDL times and if necessary, your stops.

A lot of this should be covered in your OW class.