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

[rusticitas]

I have a 5lb CO2 canister, with a Rex Grigg regulator setup. This includes a low pressure regulator (LPR), and needle valve. The diffuser I have been using is one of the "nano" glass kind sold by Aquaticmagic on eBay.

The problem is that I go through at least two 5lb canisters per month. (It was the same when I had it connected to a larger diffuser in a 20-long, or the 15-gal.) I am frustrated and stumped, but have a theory which I cannot prove (yet).

If I follow Rex's instructions to setting up the canister and regulator, this is what I do (please point out anything that I may be doing wrong):

1. Let the canister warm up to room temperature
2. Use a Permaseal washer between regulator and canister
3. Tighten regulator nut well
4. Open canister valve fully
5. Plug in the solenoid to open regulator airpath
6. Adjust main regulator to 10-12 psi
7. Starting with LPR adjustment screw screwed in all the way (flush with LPR body), unscrew 7-8 full turns.
8. Unscrew needle valve fully

At this point nothing is happening, or happens in the diffuser. There is also no discernible air venting from the LPR vent hole.

If I screw in the LPR valve to ~3 turns I then start to see bubbles out the diffuser. Air is now venting out the LPR vent hole. If I put my finger over the vent hole, the bubble/misting rate increases out the diffuser.

It is my understanding that CO2 vents out the LPR's vent hole only when there is a disparity in air pressure from the regulator to the LPR (or something like that, I am a little vague on this). So, if I open up (unscrew) the valve on the LPR to where I am not able to discern any CO2 venting out the LPR's vent hole, then I do not see any gas/bubbles emanating out of the diffuser.

My theory is that these Aquaticmagic glass diffusers are messing up the typical setup. I guess they require a lot more CO2 pressure? So when I finally get bubbles, there is a disparity between regulator and LPR, thus venting CO2 out the LPR's vent hole, and thus depleting the CO2 canister much more quickly than normal.

If so, how can I go about configuring the setup so I can get bubbles and actually have a 5lb canister last more than 1-2 weeks? I cannot figure out the correct procedure to doing this, and it is DRIVING ME NUTS.

The only consolation I have is that I am able to refill the canister for about $5.50.

Help!

-Jason

 

[VaughnH]

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.

 

[rusticitas]

I'm using Rex Grigg's regulator configuration.

I never thought of looking for leaks with a soap solution. "Duh!" to me! That was pretty obvious, and thank you for pointing that out.

Why is the regulator psi so high as you recommend, over the 10-12psi that Rex recommends? I'm confused over these parameters because the "mechanics" of them do not make sense to me yet.

 

[VaughnH]

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.

 

[rusticitas]

Let's assume that for now I keep the low pressure regulator (mostly because I'm not comfortable yet disassembling anything at the moment). What is the correct troubleshooting procedure once I've checked for and prevented any possible leaks?

1. Adjust main regulator screw to "X" psi?
2. Open/Close the LPR?
3. Open/Close the needle valve?
4. Go to step n, repeat ...

This is the part I need help with. i'm not sure which is the cause and effect as there seem to be time lags, or pressure readjustments, then I get confused about what is the next best step. What seems logical at the time isn't quite panning out for me.

Thanks for all of the help so far!

-Jason

 

[milesm]

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.

 

[fjf888]

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

 

[VaughnH]

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.

 

[tedr108]

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.

 

[VaughnH]

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.

 

[Crazy Loaches]

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.