wrote in message
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On 6 Jul 2007 00:08:26 GMT, Clark wrote:

"SteveB" wrote in
:


"Clark" wrote

You're close Steve. Fresh water is 0.433 psi/ft. I believe that 0.45 is
commonly used for salt water.

Commercial diver's training school was many years and many brain cells
ago. I knew there was a .433 in there somewhere.

There aren't very many folks that have to be concerned about the small
differences.

Where'd you dive? I worked with divers in the GOM a few times.


I think you folks missed the "300 pounds per square FOOT"
That is a couple PSI, 55-60" of water, certainly well within the
suction head of a pool pump.
The fix is simple, a vent to air and/or a second drain path. That's
why one or both are required in the code.
In my pool I have 3 parallel drain paths and a vent.

Once you have your face underwater, it's all pretty much the same.

Steve