Deadly Down Current

[z3r0c00l]

I agree -- gas planning is the bottom line regardless of capacity. However, I think Don's contention is that he (and I) prefer higher capacity (as well as a slung pony) simply to provide a higher margin of error, whether it's to compensate for a higher SAC, or unexpected conditions...

As for reg performance at low pressure -- I've breathed a tank down to zero on the surface of a quarry (did it on purpose, just to experiment, since next stop for the tank was a viz inspection). I was using an Atomic B2, and experienced no difference in pull or supply on the very last available breath, as I did breathing it at 2000 psi. (One of the reasons I love the Atomic). True, it was on the surface at 1 ata, however, if you've ever dove an Atomic, you'll notice there's no perceptible change in breathing whether you're at 10 feet, or 110 ft.

Well that appears to breath down to a very low gradient - so depth would only add arithmetic reductions via the PSI at depth. So if you were at 50 psi depth you should ideally be able to go to 50 psi, which is still nothing. That is exceptional performance if it is typical of that reg.