CO2 blowout

[tomterp80]

I had been warned about this, but still wasn't expecting it. In my 75g I use a high pressure CO2 system, unlike the vast majority of you. I have a regulator on top of a 20# tank, which has been in continuous use for about 5 years now. The regulator reduces pressure to about 18 PSI, which perks through an Eheim ceramic disk reactor, which does a decent job of breaking the CO2 into small bubbles. There is no needle valve, no solenoid shut off apparatus.

I've been working long hours and got home late again last night, and checked in on the tank, and the fish were gasping at the top or bottom, in obvious huge distress. I've lost at least one rummynose and can't find my lone angelfish. Cherry shrimp, normally scarce, were cruising around the tank abnormally. Then I noticed the huge piles of bubbles blasting through the reactor. Apparently, and I had read this a long time ago, when the tank is near empty, the pressure can fluctuate wildly, causing erratic performance. I always though it could go down, not up, but I think this is what was happening. So I need to get my tank swapped and readjust the regulator. Hope things are somewhat normal when I return home tonight.

Anybody have similar experiences with excessive CO2?

[Ghazanfar Ghori]

Classic end of tank dump. For peace of mind - I'd invest in a solenoid valve
and hook that up to a pH controller.

[krisw]

Or, you should also be able to hook up a low-pressure exhaust regulator that a number of us have been talking about trying for this very reason. When the pressure drops, it'll bleed off the CO2 into the room, instead of the tank. That said, I haven't tried it yet. Kevin or Cristy, have you?

[Cristy Keister]

Just got mine - haven't hooked it up yet. Did you figure out what other parts/adaptors we need?

[SCMurphy]

When you get to the end of a tank's life the liquid CO2 in the tank all becomes gas and that is when a dump happens. In my situation with the needle valves I use and the way I split the output from the regulator to 3 or more aquaria I never have a problem with a dump. I just run out of CO2.

You should put a needle valve into your system and your regulator must have a pressure relief valve built into it to prevent the dump in your situation. A solenoid will help a little, but I've seen those fail for other reasons too many times to risk trusting one.

[tomterp80]

You should put a needle valve into your system and your regulator must have a pressure relief valve built into it to prevent the dump in your situation.

If I put a needle valve in, that spells the end of the Eheim reactor I believe, since it needs substantial pressure to force the CO2 through the disk. Not that there aren't alternatives, but I was kind of fond of the old piece of hardware.

[Aaron]

The Eheim diffuser will still work with a needle valve in place.