5lb CO2 empties in a week; frustrated/stumped with configuration!

In my opinion you don't need the "low pressure regulator". That is not a regulator, it is a relief valve. Next, the Permaseal washer does not work for all CO2 bottles and regulators. My bottle, for example, has a groove in the sealing face of the fitting the regulator screws onto. The O-ring in the Permaseal washer drops partly into that groove, preventing it from sealing. The old fashioned seal washers work fine, and are available free from the CO2 supplier. The only requirement they impose on you is that you use a big wrench and tighten the nut at that connection as tight as you can, then do so again, until you can't turn the nut any further.

You clearly have a leak, and a big enough one to easily find with soap solution. Just soak every single connection between the cylinder and the diffuser with the soap solution and wait a few minutes, then look for mounds of tiny bubbles - those are leaks.

What regulator do you use, Milwaukee, etc.? Also, you should be adjusting the regulator to about 20 - 30 psi setting, and using the needle valve to control the bubble rate. Once you get close to the bubble rate you want you can also use the regulator adjustment to make fine adjustments in the bubble rate.

 

The goal in setting the regulator pressure is to arrive at a stable X bubbles per second CO2 flow. You do this with the needle valve and the regulator pressure adjustment. I found with my Milwaukee "all in one" regulator that my bubble rate was not stable at pressures lower than about 20 psi, so I now set it at 20-30 psi, then after getting close to the right bubble rate, I do fine adjusting by changing the regulator pressure. It works well for me. Another reason for using the higher pressure is that some diffusers take more pressure to drive C2 through them reliably than others do. When I started doing this I had one of those diffusers. Now I don't, but I still use the higher pressure just for stability.

A different regulator and needle valve might work better at some other pressure, so you have to experiment until you find the best combination of pressure and needle valve setting.

 

i think rex says to repeat step 3, attaching the regulator to the tank, something about "getting manly with it"

my 5 lb has been going for 1 year (next week) at 3 - 4 bps.

 

How large is your tank? If you have a very large aquarium a 5 lb won't last that long. Mine lasts a month on my 72g.

The only other thing I can add is that you should open up the main valve on your CO2 ALL THE WAY. If you do not that can also cause a leak.

Fred

 

I agree - that is the valve on the CO2 tank. It isn't made to operate anywhere except wide open or fully closed.

 

teflon tape

My Milwaukee regular also has a washer to go between regulator and canister. However, my Milwaukee instructions say something to the effect: use teflon tape on the threads or you will probably have a leak.

 

The CO2 connection that is standard for all CO2 bottles in this country, seals on the face of the male threaded fitting on the bottle. If it leaks there, no amount of teflon tape is going to stop the leakage. Only a good washer, with the fitting tightened with a big wrench, very tight, will stop the leaks there. You may have to retighten it a couple of times if you hook up a freshly filled, and very cold bottle.

EDIT: Teflon tape "seals" primarily by lubricating the threads so you can tighten it more easily. Given that, a single layer of teflon tape might make it easier to adequately tighten the fitting.

 

Be advised that teflon tape could also potential destroy your reg and clog your needle valve if a tiny bit of it comes off inside and goes into the reg. It's not really needed.

BTW my 15# tank on my 75g is at 2.5years so far on its initial fill at about 3-4 bps.