how much air do you use?

[FreeFloat]

...although I haven't been diving 80s. I've been using just steel 72s.

So to borrow your formula:

2250psi/69cu ft = 32psi/cu ft

I got the 69 cu.ft. by extrapolating from the "AL80" in your example, and assuming that a steel 72 was "off" by about the same percentage.

So that means my current SAC rate is closer to .90 cfm.

And that my all-time best was .53cfm.

Does that make more sense??

 

[Charlie99]

FreeFloat once bubbled...
So to borrow your formula:

2250psi/69cu ft = 32psi/cu ft

Does that make more sense??

Yes, provided that's the capacity and service pressure of your steel 72. There are other 72's (Faber/Scubapro IIRC) that are 71.4 cu ft at 3000psi,which of course is 42psi/cu ft. And there is the OMS tank which is 66cu feet at 2400, and 72.6 at the 10% overfill of 2640, and ..... ...... anyway, you've got the idea right.

 

[FreeFloat]

...it's much more complicated than I thought!!! :crazyeyes:

They're 'rental' tanks, I end up with different ones every time. I used 69 cu.ft as a ballpark figure.

Service pressure for al of them seems to be 2250 psi although they can be and have been slightly overfilled, as much as to 2400 psi when leaving the shop. (Although with recent outdoor temps, they'll be reading 2100 psi by the time they get to the site....)