The Planted Tank Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
1,079 Posts
Discussion Starter #1
I have an issue with a pressurized system split to two and a 10lb tank. The high pressure gauge was reading in the red zone and clearly down to zip/zero for at least two weeks despite the fact that Co2 was still being dispersed.

I don't know if it's the reg. Took it off and it will be checked out.

It was a new canister lasting only 5-6 months and it was only on two 15g tanks. I may have had a leak or the tank wasn't filled properly. I read somewhere that a "new" tank is never really full. My 15lb tank ran for almost a yr and that was split three ways, 2 leads to a 55g and 1 to a 20g long.

I have to refill the 10lb. Should I open the valve and release whatever gas is remaining? Would this be a bad thing to do and why?
 

·
Super Moderator
Joined
·
11,971 Posts
When you get your 10 lb tank refilled, I would double check for leaks, etc. Having it last only 6 months of two 15g tanks is a bit low, unless your bubble rate was set extraordinarily high.

All tanks are never filled "all the way up." They are filled approximately 3/4 the way up, I believe.

There is no need to release the CO2 before you refill the tank.
 

·
Registered
Joined
·
1,079 Posts
Discussion Starter #3
Bubble rate wasn't any higher than for the other tanks. Maybe even less since they're only 15g's.

Yeah, thought it should have lasted longer than that.

Having the reg checked out too. After I get that back, I'll set it up and check for leaks.

Does anyone know how much pressure a 10lb should be at when it's full?
 

·
Super Moderator
Joined
·
11,971 Posts
Tanks are filled by weight, and the PSI that is indicated by the regulator is not an accurate gauge of whether you have the full amount of gas or not.

That being said, tanks in general will be ~800-900 PSI when they are filled (and have been brought up to room temperature. Prior to this, they will be cold, and the pressure will seem low).
 

·
Banned
Joined
·
5,009 Posts
...
Does anyone know how much pressure a 10lb should be at when it's full?
I have you covered here.

FROM: http://www.plantedtank.net/forums/p...re-relation-room-temperatures.html#post287886
madman280 said:
When a CO2 tank is reasonably full it will contain a mixture
of both CO2 liquid and vapor.

As long as both liquid and vapor are present,
the pressure in the (CO2) tank will depend only on the (ambient) room temperature (not "fullness")
as shown in the table below:

Tank Temperature Cylinder Pressure
(F) (PSIA)
@69° 837
@71° 859
@75° 905
@77° 928
@79° 952
@81° 976
@89° 1080

The gauge pressure (PSIG) is approximately 14.7 psi less than the values in the table above. The temperature to pressure relationship is logarithmic. That's why its not a good idea to leave a full cylinder in your trunk on a hot day.
The following link has information about the markings on metal compressed air and CO2 cylinders.
http://www.pbnation.com/showthread.php?p=46930222#post46930222
 
1 - 5 of 5 Posts
Top