CO2 flow meter

Subject: CO2 flow meter
> I believe the flow meters are used in welding applications
> where an inert gas is required to prevent oxidation of the hot
> metal. The flow rates are much higher than those required for
> aquaria. When I was making inquiries, the price for these thing
> was quite high and comparable to that for regulators. Most
> regulators with gauges are designed for compressed oxygen
> and the welding supply guy told me that the acidic CO2 gas
> will corrode them. 

The regulators I have (made by two different companies) are 
specifically designed for CO2 use.

> A gauge won't tell you much because
> compressed CO2 is a liquid with a constant gas pressure (for
> any given temperature) and this won't change until the
> the liquid CO2 in the tank is all gone. From that point it
> is a very short time before you need to re-fill the tank.

Actually, the gauges are quite useful.  The tank pressure gauge,as 
you mentioned, does not start to go down until the liquid CO2 is 
used up.  Still, at the rate I use CO2 in my 70G tank, I have at 
least a couple of days notice that I need a new tank.

The out flow gauge is useful to bring the flow down as low as 
possible before feeding to the needle valve.

> I don't have bottled CO2 (relying upon the little yeasties)
> but I think many people keep a second smaller 5 lb bottle
> on hand while they take their larger one in for a refill.

A lot of people only _use_ 5 lb tanks.  A 5 lb tank is as heavy a 
tank as I want to tote around, and as big as I can easily hide 
under my tanks.  It also lasts over 9 months on my 70G tank, so 
it's not like I have to run down for refills frequently ;-)  
Besides, even a 5 lb tank will set you back about $50.

> Steve (encouraging members to quote their city & location
> with their sig) in Vancouver where it's STILL raining.
> Karen, send us your snow PLEASE! (frustrated skiier)

If you'll pay the freight, I'll ship you all the snow piled up 
beside our driveway.  It's a long driveway, and the banks are 
close to 6' high... You could probably build yourself a 
considerable ski slope! ;-)

Karen Randall
Aquatic Gardeners Assoc.
Boston, MA