Posted by Chuck Tribolet on June 02, 2005 at 18:48:00:
In Reply to: Best mix posted by North Coast Diver on June 02, 2005 at 16:48:47:
Best mix: air, 80 cu. ft. tank. One hour surface
inteval.
What bottom time? What ascent profile? What SAC?
And why would I want to dive a zillion dives in a day at 50 feet?
And you used to say that 35 is best mix for 100
feet. PPN2 on 35 at 100 is 2.61 atm. PPN2 on air
at 50' is 1.98 atm. Why is 2.61 OK on 35, but only
1.98 on air?
I'm not saying Nitrox is bad. To the contrary,
it's GOOD STUFF. I don't dive anything else.
But if it's OK to dive to 100' on 35, it's OK to
dive air to 76', not 50' Do the math.
Nah, you won't do the math, so here it is.
PPN2 of 35 mix at 100' is:
(1.00-.35)*(1+100/33) = 2.61
PPN2 of air at 76' is:
(1.00-.21)*(1+76/33) = 2.60
Air at 76' should be the same as Nitrox 35 at 100'
Chuck