CO2 empty already?

[JustOneMore20]

I have a 20lb CO2 tank that supplies 3 tanks with CO2 (55g, 29g, 5.5g). The bubble counts on all are 2-3bps. I filled the tank at the end of March, beginning of April (can't remember the exact date) and now my regulator is reading in the red (almost out). I find it hard to believe that I've used 20lb of CO2 that quickly. I thought it would last atleast 6 months.

I did a leak check with Windex and didn't find any leaks. My regulator is on pretty tight and just about a week ago or so it was reading 800psi and now its in the red. What gives? When I first setup my system, I had a pretty high bubble count on my 29g, but the amount of co2 in the tank wasn't declining very fast. It seems like in a week, its dropped significantly. I know the ambient room temperature has something to do with the readings, but I don't think the room temp has changed. My tanks are in a finished basement room, so its not hot down here. The a/c has probably been on more in the past month, but there hasn't been a significant change in the temperature. Also, the needle valve has been staying in the red....doesn't fluctuate.

I didn't find leaks so is there anything else I could do to make sure when I fill the tank again, it lasts more than 2 months? The other gauge is set to 11psi and somehow got bumped up to about 20psi a week ago....does that have anything to do with the tank emptying so quickly? I'm really confused here, so any advice would help.

Thanks!

 

[rkilling1]

You must have a leak. Use soapy water when you get the bottle refilled and lined back up.

As far as the level not dropping, the pressure will remain at 800 - 900 pounds until the bottle is almost empty. Remember the CO2 is in a liquid and a gas phase within the bottle. As you use some of the gas, some of the liquid is converted to gas. (PV/T) Only when there is no more liquid left will you see the pressure guage decrease. You can weigh the bottle empty and then full and monitor the weight of the bottle during use, but that's a PITA.

 

[kaz]

is it possible to fill the tub with water and place the tank under water?

 

[JustOneMore20]

Thanks. I'm getting the bottle refilled in the morning, so I'll do the soapy water test again. I have homeade bubble counters out of syringes. Is it possible for it to leak that much around the check valve that is siliconed in? I did loosen the part of the regulator that screws on to the tank at one time (not much though), so that could have been my problem, but I'll just have to see.

And it makes sense about it staying at 800 and then dropping. I didn't quite understand how that gauge worked, but I do now.

 

[30searay]

How long should the average CO2 tank supply a tank? I have a 5 lb tank that supplies my 110 gallon and it didn't last more than a month. What are other peoples experiences? I would be very curious to know.

 

[Hoovercat]

There will be a pretty wide variety but I use a 5lb. on a 29 gallon and it lasts 3 months or so. I would think a month on a 110 gallon sounds about right.

 

[Purrbox]

I'm using a 5lb tank on three small aquariums totalling 18 gallons. It runs 24/7 and the first fill lasted just over 6 months.

 

[rkilling1]

I run a 10# to two tanks. One of them is a 75 and one is a 28, so 103 gallons total. I get six months out of the tank. I would think you would get 2 to 3 months worth out of it.

 

[JustOneMore20]

So with about 89 gallons from my 20lb, I should get a year out of it! Wow. I got the tank refilled yesterday finally and hooked it back up. I plan to leak check it again tomorrow (no time today). I made sure my dad tighted up the regulator nut so that it wouldn't be leaking, so maybe I can find the spot. I can't believe it was empty after 2 months....Wish me luck.

 

[Wizzard~Of~Ozz]

I get about 6-8months out of a 10lb on a 120Gal. (now has a 23Gal sump)

I use a PH Controller. BPS is around 20 or 30 (can't really count, just guessing)

 

[30searay]

I get about 6-8months out of a 10lb on a 120Gal. (now has a 23Gal sump)

I use a PH Controller. BPS is around 20 or 30 (can't really count, just guessing)

Now I am concerned that I have a major leak somewhere. If a 5lb tank only ran for 30-45 days on my 110, and I was no where near 20-30 bps, running at about maybe 6-8 bps with a pH controller, something is up. I've got a 10lb tank hooked up now but I would bet my leak is in the bubble counter (the water does evaporate over time). Do you seal your bubble counter? What about the air tubing - do you use something special?

 

[Atl300zx]

my 5 lb on my 55 Gallon is at 2 months and counting. I keep my Co2 at 50 ppm.

 

[Purrbox]

When using a PH controller the bubble count isn't that important, since it will shut off as soon as it hits the tartget PH. With a higher bubble count it will get there sooner and shut off soon (perhaps with a touch more overshoot due to delay time).

There could be a leak in the bubble counter. You'd need to spray it with leak check solution (soapy water) to see if it's forming bubbles anywhere. If the leak is at one of the joins and not a connection that can be tightened down, you'll probably need to remove/replace it as I doubt you'd be able to fix one of the commercial units. The water in these will evaporate over time even if there isn't a leak just with the CO2 flowing through it. This is completely normal, and the water just needs to be replaced periodically.

You can use regular airline tubing, but it will need to be replaced at least once a year since ht CO2 will slowly break it down. You can also get CO2 resistant tubing which shouldn't need replacing.

A common place to have a leak is at the gasket where the regulator connects to the cylindar. It's not just a matter of tightening the bolt down really hard, if the gasket is bad you'll never get a good connection. If you're using a plastic gasket, then it's a good idea to replace it every time to ensure a good seal. The rubber gaskets that are attached to the tank should last quite a bit longer and I've found seal much easier.

 

[Wizzard~Of~Ozz]

I get about 6-8months out of a 10lb on a 120Gal. (now has a 23Gal sump)

I use a PH Controller. BPS is around 20 or 30 (can't really count, just guessing)

Now I am concerned that I have a major leak somewhere. If a 5lb tank only ran for 30-45 days on my 110, and I was no where near 20-30 bps, running at about maybe 6-8 bps with a pH controller, something is up. I've got a 10lb tank hooked up now but I would bet my leak is in the bubble counter (the water does evaporate over time). Do you seal your bubble counter? What about the air tubing - do you use something special?

I use Blue silicon tubing running to Phosban reactor (empty, just water) for a reactor. This can diffuse Co2 into the waterstream @ about 50BPS max.

I'm curious, did you weigh the tank before and after the fill? It's generally a good idea to weigh it empty, then you can put it on a scale and check the actual weight added (should be 10lbs)

The only other minor thing, I don't push my PH much beyond 1 point below normal (I run @ 6.8 - 7, sitting is ~ 8.0) I find it takes twice as long to get it much below that. (diminishing efficiency).

 

[Alshain]

Just FYI, I work in the Natural Gas industry and as you can imagine we work a lot with pipes and pressure. People around here are always trying to use Windex to test for leaks and it just doesn't work. I don't understand it really, its not even that soapy.

 

[Lonewolfblue]

I used Windex on mine and had found my leaks. Now I have things tightened up, and it's looking good.

As for length of time, I had a 5lb on my 75G that lasted just over 6 months. Now I have 20lb bottles, and they should last me quite a long time.