On Sun, 4 Apr 2010 18:05:47 +0000 (UTC), Elmo wrote:

http://www.truetex.com/carbonation.htm

Given a co2 tank at 72°F has a pressure of 860 psi (as long as there is
some liquid still in the tank) according to this nice C02 tank care
article:
http://www.reefscapes.net/articles/b...co2_tanks.html

I'm curious ...
Q1: How do you know when you're "almost out" of liquid in a C02 tank???