CO2 tank - when to swap/refill

LegoZ81 · Feb 25, 2010

Pressure is dropping on my cylinder and I am approaching 500psi I have had the tank for a year now and since it is a 10lbs tank I have not yet had to refill it. I need to know how low I should let it go before i take it in to swap it out. Any suggestions?

Caleb Bruyn · Feb 25, 2010

LegoZ81 said:
Pressure is dropping on my cylinder and I am approaching 500psi I have had the tank for a year now and since it is a 10lbs tank I have not yet had to refill it. I need to know how low I should let it go before i take it in to swap it out. Any suggestions?

I always wait until it is gone or almost gone like10 psi. Especially if you already know where to refill your tank. I have a spare but never really use it. If i run out for a couple of days my water never gets low on calcium. So don't worry too much unless you have a bare bottom tank and then you might exchange it sooner than later.

AZDesertRat · Feb 25, 2010

CO2 is filled by weight not volume or pressure so its hard to judge how much is in there unles you weigh the bottle. I let it go empty or very near before filling mine, the gauge is not real helpful here.

gilmour01 · Feb 25, 2010

if a full tank is around 2000 psi, then you could assume that your 3/4 of the way thru it and probably have 3-4 mths left. that would just be an estimate though. and i've been drinking so my math skills may be failing me.

Corigan · Feb 25, 2010

You will notice pressure changes if there is a change in temperature. If there is no ambient air temp change around the cylinder and the pressure is dropping, than that means it is near empty. The co2 is a liquid in there. Once it is all gone, all that is left is the gas and if it is loosing pressure that means it is running real low. I usually just swap out once the pressure starts dropping. Once it turns into the gas only stage is when it starts dropping pressure so the end is extremely near depending on your bubble count.

AZDesertRat · Feb 25, 2010

Pressure gauges are not very helpful with CO2. It wil be cruising along at 500 psi then boom its zero, again they are filled by weight not pressure. The pressure could read 500 then you set the bottle in the sun and its 1000 psi. Check the tare weight of the bottle and the actual weight and that tells you how much is in there. When they fill it they put it on a scale.