5 lb. cylinder of CO2 lasted only 33 days

I run a 20# on 60 gal and it will last 3-4 months. The tank has overflows/Sump and CO2 is on for 11 hrs a day. This isn't to far off yours. If you have done all for leaks then that may be the bottles longevity. If practical you might trade up to the next size if your vendor is willing.

BTW leaks can be hard to find even with soap water.

 

I use a 5 pound bottle on a 45 gallon tank, and the last bottle lasted from Sept 11 to November 29, about 78 days. You may just be using yours at a higher bubble rate, relative to the tank size, than I do.

 

Rockster:

Take your big wrench and re-tighten the regulator to the CO2 canister for a second time the day after your first attachment. I'll bet you get another 1/8 to 1/4 turn.

If you are using the cheapo plastic washers (which I use) between the regulator and the canister, I hope you get a new one with each refill. There are some very cool brass washers with rubber in them that are basically life-time washers.

Lastly, I assume your silicone tubing fits very snugly onto the check valve -- should be difficult to get on -- hopefully you have to heat your tubing to get it on. I was using a cheap plastic check valve at one point that leaked slightly. Rather than buying a better check valve, I cheated and put the check valve under water and it stopped leaking.

 

One obvious reason why some of our CO2 usage is abnormally high - our diffusion method sucks. I'm not pleased with my external reactor set up yet. So, I'm thinking about alternatives.

I use a 12 inch long crescent wrench to tighten the regulator fitting, and leak check it each time. This time I waited until the CO2 bottle reached room temperature before even attaching it. The connection was still tight today, one day after hooking it up. I do reuse my nylon washer, carefully putting it back just as it was before. It always passes a leak check.

 

If you have a solenoid, check what PSI that is rated for. I had been burning through my CO2 tanks, and just happened to see the manual that said the max PSI was 5. I had been setting it for 10. It was probably a couple of months ago that I figured this out, and I'm still on the same tank.

 

I use 600g bottles on my 33USG at 2-3 bps (120-180bpm) which are about 1¼ pounds.

These last me 2-3 months using a glass/ceramic in tank diffuser!!!

AC