> From: gomberg at wcf_com (Dave Gomberg)
> Tyson, if you doubt what I say, try tank+FROG+gauge+needle-valve in
> that order and close the needle valve.  The gauge will rise to 800PSI
> or so.  CFM is not pressure, it is flow.  The FROG is a Flow
> Regulator, not a pressure regulator.  Flow and pressure are highly
> correlated, stop the flow and the pressure will go through the roof.
> Don't injure yourself, use proper equipment.

Dave, this setup is being sold by a local shop and works very well, no
matter what the theory says.  

> From: Erik Olson <eriko at wrq_com>
> Can normal needle valves withstand 800PSI of pressure directly?  I
> read a post on here or rec.aquaria once of a guy who didn't use a
> regulator at all, but just hooked a needle valve directly to his CO2
> bottle.  

The Dupla "Starter Kit" I started with lo these many years ago had a
needle valve that attached right to the CO2 bottle, a check valve, a
plastic diffuser doodad and some silicone tubing.  The needle valve
did just fine "regulating" the 900 psi bottle pressure although it was
a tad sensitive to adjust.   

George Booth in Rather Chilly But Sunny Colorado