# CO2 Tank reads 700 PSI, fast drop



## UDGags (Sep 13, 2009)

*Re: 700 PSI Tank*

20lbs last me 2.5 months on my 125 as reference. If you're way off from that than you prob have a leak somewhere.

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## exv152 (Jun 8, 2009)

I'd say you have a leak somewhere. I have three 10lbs tanks and none of them run out that quickly, they usually last about a year, sometimes a bit more. Have you tried spraying soapy water over the other components too, like the solenoid, bubble counter, top of the co2 bottle, etc? The temperature of the environment where the co2 cylinder is can also affect the weight.


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## puopg (Sep 16, 2012)

im not sure if I agree with temperature affecting the weight as that basically is saying mass decreases with respect to temperature. I have indeed sprayed most if not all connections with soapy water. I do not think i saw a leak, i would imagine it would be rather evident that a leak was there as bubbles shouldve been visible. Correct me if i am wrong here. I know the solenoid works since co2 is completely shutoff. I have only tested the tank connection to the CGA320 adapter or w/e that thing is that screws into the tank. That showed no problems. i do not have a bubble counter, but what i can say is i bubble the co2 into the filter circuit (ehiem 2213) and its traveling at about 1 bps. So IMO, thats not that much.


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## hamato (Jun 7, 2008)

I have a 20g and a 10lb lasted over a year before the pressure started to drop. I'm putting out enough CO2 to stress my fish, but it currently isn't being diffused all that efficiently so the levels stay fine. 

Couldn't hurt to check your hose barb connections if the tubing is old. I had a leak recently that only occurred when I bumped the tubing the right way. This is only really a concern if you have tubing between the needle valve and reg though.


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## TwoTacoCombo (Apr 13, 2012)

Temperature can affect the pressure inside the tank. If you have about 3 pounds of CO2 left (by your math), then you still have liquid in the tank. If you still have liquid, then your pressure drop cannot be caused by the tank running 'empty', which only begins to happen after all liquid is exhausted and all that's left is gas. I've seen my tank run below 800psi in the winter, and 900+ in the hot hot summer. Also, most tanks aren't filled to capacity; more like 80% or so.


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## drewsuf82 (May 27, 2012)

I've got a 20 lb tank on a 55 and it lasts a good long time (3 months right now and still reading good pressure)

I would def take some soapy water and check all of your connections, every single one of them...if you don't see any bubbles actively forming or moving I would start checking your hoses

Hope this helps


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## puopg (Sep 16, 2012)

Ok thanks all, will do thourough check tonight. Do i just mix soap + water and shake it to get it a bit foamy? or no foam at all?


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## PlantedTankRookie (Feb 21, 2013)

puopg said:


> Ok thanks all, will do thourough check tonight. Do i just mix soap + water and shake it to get it a bit foamy? or no foam at all?


soap and water mixed, no foam required. The leaking CO2 will create foam so you can identify the location of the leak.


With smaller setups, I'd just submerge the whole unit into a filled bath tub. Unplugged and removed from the tank obviously. Watch for bubbles.


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## Bettatail (Feb 12, 2009)

what is your room temperature at night?

and normally if the co2 tank is not 650 psi or below, it is too fast to conclude that the co2 is running out, and the right way to measure how much co2 in the cylinder is to weight it.


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## exv152 (Jun 8, 2009)

Take a spray bottle, add some dish soap, then spray. You're looking for moving bubbles, sometimes it's obvious and other times it not. But I'd say you have a definite leak somewhere. Ambient temperature will affect the pressure in your cylinder, not sure if it also affects the weight.


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## puopg (Sep 16, 2012)

Bettatail said:


> what is your room temperature at night?
> 
> and normally if the co2 tank is not 650 psi or below, it is too fast to conclude that the co2 is running out, and the right way to measure how much co2 in the cylinder is to weight it.


Ambient temp is ~60-70 i think. I think the thermometer is off since it seems cold in the mornings to me, but heh might jsut be my bed is warm. I weighed it and since TW is 30 lbs + lets say 4 lbs regulator, thats only 3 lbs co2 left of a 10 lb co2 tank within a month.


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## PlantedTankRookie (Feb 21, 2013)

"Additionally i closed the tank main valve and let it sit overnight. The tank pressure gauge did not change."

Is this gauge on the tank or on the regulator?
In other words: When the tank valve is closed, are you reading the pressure inside of the tank or the pressure in the line connected to the tank?


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## puopg (Sep 16, 2012)

PlantedTankRookie said:


> "Additionally i closed the tank main valve and let it sit overnight. The tank pressure gauge did not change."
> 
> Is this gauge on the tank or on the regulator?
> In other words: When the tank valve is closed, are you reading the pressure inside of the tank or the pressure in the line connected to the tank?


On the tank. I followed the leak test by bettatail for that part.


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## Bettatail (Feb 12, 2009)

puopg said:


> On the tank. I followed the leak test by bettatail for that part.


if the co2 tank shut, the pressure gauges of the regulator stay the same, it means:
Regulator is ok(from cga320 connection to solenoid), cga320 to co2 tank connection is ok.

1.check the connection between the solenoid and the metering valve. due to the rate that the co2 in the co2 tank dropping fast, if there is leak between the solenoid and the metering valve, should be a large one, or there is no leak.

2. check the relief valve on the co2 tank.

If non of above, there are things that maybe skipped.

1.
get a bubble counter and monitor how many bubbles per second, to be sure.
The main purpose of bubble rate is to monitor the steady flow, and it is not that accurate to use bubble counter to [STRIKE]monitor[/STRIKE] calculate flow volume, but normally, the bubble is about the same size if use water, so a large flow means more bubbles.
if a co2 tank can last 10 month on one bubble per second, bubble rate double, the co2 tank last 5 month, three bubbles, co2 tank last 3-4 month, 4 bubbles, co2 tank last 2 and a half month...
know your co2 exact flow rate(bubble rate) will help alot.

2. 
60-70 degree temperature, the pressure in the co2 tank can be lower, it is about 650-700 psi in the winter month that I saw on the gauges of the regulators, when the room temp was around 50-60.


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## puopg (Sep 16, 2012)

Bettatail said:


> if the co2 tank shut, the pressure gauges of the regulator stay the same, it means:
> Regulator is ok(from cga320 connection to solenoid), cga320 to co2 tank connection is ok.
> 
> 1.check the connection between the solenoid and the metering valve. due to the rate that the co2 in the co2 tank dropping fast, if there is leak between the solenoid and the metering valve, should be a large one, or there is no leak.
> ...


Thanks bettatail. I will check the following. Where is the relief valve on the tank? I'm not at home so can't picture it in my mind. And if the bubble is same size in water, then its 1bps since its traveling thru my water filter tubing and i can see it as its going. Haha i can finally use that bubble counter you included with my other regulator perhaps.


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## Bettatail (Feb 12, 2009)

puopg said:


> thats only 3 lbs co2 left of a 10 lb co2 tank within a month.


I think it is the low temperature, because if there is 3lb of liquid co2 remain, the pressure is still around 800 under normal room temperature(70-80).



puopg said:


> Where is the relief valve on the tank?


opposite the CGA320 connection port on your co2 tank.


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## puopg (Sep 16, 2012)

Update with tonight's results:

I tested with soap water on all connections i could possibly see by using a syringe and squirting the solution on those connections. None showed noticeable leakage. I tested all on the tank itself and still no noticeable leaks. The only possible explanation I have for the severe decrease in tank weight is:
1. Was never full to begin with
2. Tank is not properly labeled weight
3. Scale I use is inaccurate. 

Well, i guess I will know once my CO2 begins running out where exactly my tank level is at. Will update...whenever that happens.


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## puopg (Sep 16, 2012)

Posted a video. Just had a chance to attach a bubble counter. Now all my livestock are alive just FYI, but anyone might this be the reason how i went through my CO2 tank so fast?

https://www.youtube.com/watch?v=ONCfhrNjD7Q


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## byork (Sep 28, 2012)

My regulator always reads almost 750-800 psi on a new tank. Maybe my gauge is wrong. Even so if it is it is consistently wrong. A 30# tank lasts about 4.5 months on a 155 system. I have tested it for leaks repeatedly but I am pretty sure there are none. Maybe it is the gauge or the temp or atmospheric pressure in the room either way as long as it is consistent that's all that matters to me. Have you considered the gauge?


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## puopg (Sep 16, 2012)

The gauge is dropping to 600 PSI today. It definitely seems to be running low. Its like 75 F in my room.


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## Bettatail (Feb 12, 2009)

puopg said:


> Posted a video. Just had a chance to attach a bubble counter. Now all my livestock are alive just FYI, but anyone might this be the reason how i went through my CO2 tank so fast?
> 
> https://www.youtube.com/watch?v=ONCfhrNjD7Q


too fast!


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## exv152 (Jun 8, 2009)

It think you still have a leak. If the CO2 was full at the beginning of March there's no reason for it to run out now on a 10lbs. Have you checked the relief valve? On your CO2 tank it's the valve opposite the CGA320 connection. See picture. I've seen some folks have CO2 leaks there.


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## puopg (Sep 16, 2012)

Like i said earlier, i have checked with the soap water method. If it was all noticeable, i would've seen it. I drenched that sucker. Else, there must be another way to test it. But seeing as how my BPS was like 10 or something, that makes sense as to why.


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## TwoTacoCombo (Apr 13, 2012)

Like bettatail said, that's way too much gas. On a 10 gallon, your rate should be closer to 1BPS. I run less than that on my 20 gal. You're probably just dumping most of that into the atmosphere, as I doubt the majority of it is getting dissolved into the water before it leaves the tank.


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## puopg (Sep 16, 2012)

TwoTacoCombo said:


> Like bettatail said, that's way too much gas. On a 10 gallon, your rate should be closer to 1BPS. I run less than that on my 20 gal. You're probably just dumping most of that into the atmosphere, as I doubt the majority of it is getting dissolved into the water before it leaves the tank.


Yes i agree.


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## AlanLe (Jan 10, 2013)

Narrow the problem by connecting your reg to another working /no leaking tank (if you have one). If leaking still occurs then you know it's not coming from the tank.


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## puopg (Sep 16, 2012)

Yea ran outta co2, had to refill tank


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## exv152 (Jun 8, 2009)

Hope you were able to get to the bottom of this, these kinds of things can be aggravating.


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