Here's the results of the experiment I ran

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Posted by Chuck Tribolet on April 13, 2005 at 14:55:03:

In Reply to: Re: DIS posted by Chuck Tribolet on April 13, 2005 at 07:45:23:

Here's the results of the experments I ran. They
were originally posted on the UWphoto list 9/5/2000.

I took a full
AL80 and I put my Atomic Aquatics B1T2 on it. The Oceanic
DataMax Pro said 3090 PSI. I closed the valve, drained the
regs, and removed the air integrated computer. I opened
the valve on the tank all the way for two minutes, making
loud hissing sounds as it vented through the HP port,
closed it, and reinstalled the computer. It was down to
2350 PSI. That would be 6.75 minutes to drain to 500 PSI
assuming a constant flow rate (and the flow rate would drop
off somewhat as the pressure dropped off, so it would be
more than 6.75 minutes)

First stages have a small orifice under each HP fitting for
exactly this reason. Maybe your rental reg was so old it
didn't have one, or some idiot had drilled it out, or

I decided to run a second experiment, this time on the LP
side. Same AL80, at 2450 (it had a day to warm back up).
I pulled the octopus off and opened the valve. It made a
huge noise (every dog in the neighborhood started barking,
including both of my Newfies), tried to knock the tank
over, and was generally much more dramatic. I could watch
the pressure on the gauge, and quickly figured out that
this better be only a 30 second test. After I closed the
valve at 30 seconds, it was down to 670 PSI.

The results of this experiment are going to be dependent on
the quality of the first stage. I know the Atomic's
inflator hose will run air tools that my old Dacor
wouldn't. That tells me the Atomic has good flow (or at
least better than a 14 year old Dacor)


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