CO2 Needle Valves

Jason B · 12-02-2002, 10:49 AM

I have a pressurized CO2 system. My problem is that when the bottle nears empty the needle valve will let the bottle empty rather quickly. It will go from 2 bubbles a second to 8 or 10 (basically uncountable). It sends my Ph down .6 to .8 below normal. If I catch the problem the needle valve can be readjusted back to 2 bubbles a second. I tend to lose a fish or two each time it happens.

I've heard about this problem happening to others but I don't remember the solution. Also I have a system made for aquarists, not a home made one from a welding shop.

gcvt · 12-02-2002, 12:05 PM

Does your cylinder pressure gauge indicate a drop in pressure before the bubble count starts increasing?

Jason B · 12-02-2002, 12:28 PM

What happened is I heard the bubble counter bubbling like crazy and checked on the system. I noticed the pressure was near the bottom. I then readjusted the needle valve and the next day the cylinder was empty. So I can't say if the pressure guage dropped before the bubble count increased.

gcvt · 12-02-2002, 1:15 PM

I'm not sure if there is an easy solution to this problem. I had my 10# tank filled last March and I've only looked at the gauge about 20-30 times. I've heard 10#'s should last about a year so I'm going to check that gauge every day, once January rolls around. Hopefully I'll catch an indication that's it getting empty before it dumps. Maybe someone else knows a better way to deal with this?

EDIT: - Jason, what size is your tank?

125gJoe · 12-02-2002, 3:06 PM

Quote:

Originally posted by gcvt
....so I'm going to check that gauge every day, once January rolls around. Hopefully I'll catch an indication that's it getting empty before it dumps. Maybe someone else knows a better way to deal with this?

That's what I have also heard. CO2 tanks will "dump" an excessive amount of CO2 when the supply in the tank drops. That's just how the system acts... So, watching it more closely when levels in the tanks starts to get low is the only way to prevent the "dump" of CO2. Time for a re-fill...

Jason B · 12-02-2002, 3:40 PM

I have a 5lb cylinder. I check the gauge periodically and it stays steady.

I thought I heard before it was the quality of the needle valve which let the tank dump. If it's a question of watching the system that can be managed too.

Also I've had to refill 3 times in the last year. At 3 bubbles average per second is that excessive? I have a 90 gallon.

gcvt · 12-02-2002, 4:08 PM

Quote:

Originally posted by Jason B
I have a 5lb cylinder. I check the gauge periodically and it stays steady.

I thought I heard before it was the quality of the needle valve which let the tank dump. If it's a question of watching the system that can be managed too.

Also I've had to refill 3 times in the last year. At 3 bubbles average per second is that excessive? I have a 90 gallon.

Not sure on the needle valve quality question...but I might know more around March

At 3bps, I don't know that 4 months out of a 5# would be that unusual. But, have you checked all the fittings with soapy water to see if you have any leaks? I push about 1.5bps on the 10# and I was told it should last 'about' a year.

inxs · 12-02-2002, 7:21 PM

At about 2-3 bub/min I get 2-3 months out of a 5lb on a 125 - it doesn't seems like a lot. However it does go from almost full to empty in a blink.

Jason B · 12-03-2002, 8:22 AM

I plan on checking with soapy water after I set it up tomorrow. Its getting filled right now. I guess I just need to keep good notes and watch it and have a spare bottle ready to swap.

Thanks for your all your help.

inxs · 12-03-2002, 8:26 AM

Remember teflon tape is your best friend.