Posted by Frank, AADIVER, Farmer on October 30, 2000 at 13:42:26:
In Reply to: Re: 'an alert for those switching to a long primary hose...' posted by MHK on October 30, 2000 at 11:01:58:
Interesting and valid question.
I dive with two regs, one primary to my 21% 120, and one to my 40%, 40 cu ft. pony. I would only do an OE in 90' or less with 40%. Deeper, I would reduce the O2 in my pony proportionately. At no time would I have an elevated O2 in my pony in excess of 1.4. Cutting to the chase, I'd give my pony reg to the OOA diver and get the hell out of there. Anticipating your follow up question, what if my 120 was low and I'd already switched to my pony for exit and ascent? In that case, old fashioned buddy breathing would be the only option.