# My CO2 tank got empty overnight



## enb141 (24 Dec 2018)

Hi, my CO2 tank got empty over night, before that I had it running at about 2 air drops per second on a 75 US Gallon tank, the CO2 tank was 5 pounds with a tunze double gauge regulator controlled with a solenoid tunze solenoid, the CO2 tubing was from Aquatek and the bubble counter was a fluval or a plastic one, same for the co2 dissolver.

I knew the water was returning because I didn't have a check valve, but I had a solenoid so do you think that helped to drop the whole CO2 overnight, was almost full.


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## Tommy (24 Dec 2018)

I'm no expert by any means but the most likely scenario is that you have a leak. When you get a new bottle check all the connections with soapy water to see where the leak is coming from.


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## Zeus. (24 Dec 2018)

What was the bottle PSI before it went empty? 
My 500l tank eats CO2 but it normally takes a couple of days to drop from 1000PSI to nothing.
Sounds like a leak to me also.
Washing up liquid bubbles over fittings is best way to check, but be careful around electrics with the bubbles OFC


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## Tim Harrison (24 Dec 2018)

I use something like this...


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## jaypeecee (24 Dec 2018)

A few points of clarification are  needed:

1 Is your CO2 solenoid valve on a timer? Assuming it is, what duration was the CO2 set to come on for?

2 If you didn't have a check valve, then the tank water could have been siphoned back into the CO2 regulator assuming that the solenoid valve was in the ON position. But, for this to happen, the working pressure of your regulator would have to drop considerably. Please check the logic of my reasoning.

3 Is your regulator of the two-stage variety? I'm not referring to the double gauges. Some regulators can suffer from 'End of tank dump' but this occurs when the cylinder pressure is getting low.

Maybe Tommy is correct. Perhaps you had a leak in your system.


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## enb141 (24 Dec 2018)

Thanks guys, here I'm responding some questions you are asking me

- The solenoid is on a timer, it runs from 7:30 AM to 4:30 PM

The last CO2 values I got before it completely drained out were, 50 at the right gauge, 1 bar in the left gauge, those values barely moved when was full.

Thanks Tim for the tip about checking leaks with that liquid

Here is the picture of the regulator




 


I was using a plastic seal with a gum like seal so maybe that help to drain the CO2 so quickly, here is the picture about what I'm talking about


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## Barbara Turner (25 Dec 2018)

Above about 75psi your CO2 starts turning from gas to liquid, this means that the pressure has very little to do with how much co2 is in there. Once all your liquid co2 boils off, the pressure will fall like a brick.  (always weigh the bottle)
It does sound like a leak though. I try to check the joints with some soapy water and things like check valves with a bowl of water.


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## enb141 (25 Dec 2018)

Barbara Turner said:


> Above about 75psi your CO2 starts turning from gas to liquid, this means that the pressure has very little to do with how much co2 is in there. Once all your liquid co2 boils off, the pressure will fall like a brick.  (always weigh the bottle)
> It does sound like a leak though. I try to check the joints with some soapy water and things like check valves with a bowl of water.



First it wasn't almost not leaking any gas, but suddenly one night all the CO2 was gone, it didn't leak into the Aquarium because all the fish are OK but it leaked so somewhere.

By the way I'm using two seals instead of one, do you think that could help to leak the CO2?


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## Tommy (25 Dec 2018)

enb141 said:


> First it wasn't almost not leaking any gas, but suddenly one night all the CO2 was gone, it didn't leak into the Aquarium because all the fish are OK but it leaked so somewhere.
> 
> *By the way I'm using two seals instead of one, do you think that could help to leak the CO2*?



That's your problem right there! Never use 2 seals together your asking for trouble. Use only one seal and when you get some more co2 check everything for leaks.


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## jaypeecee (25 Dec 2018)

Barbara Turner said:


> Above about 75psi your CO2 starts turning from gas to liquid, this means that the pressure has very little to do with how much co2 is in there.



Hi Barbara,

I always use my cylinder pressure gauge to indicate when CO2 is running low. I have a JBL regulator where the nominal pressure is 60 bar. This pressure falls slowly when the CO2 is starting to become used up. From the point at which the cylinder pressure starts to reduce, it's a matter of many days before I need to replace the cylinder. I'm a bit confused about your figure of 75psi. According to http://howto.killerhurtz.co.uk/pneumatics.htm, "We use liquefied CO2 at about 50 bar/750psi - CO2 liquifies at about 750 psi at room temperature". I'm no expert in this field but could the figure of 75psi apply at a much lower temperature than, say, room temperature?

JPC


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## ian_m (25 Dec 2018)

CO2 is liquid at room temperature at about 55bar(800psi), as in the fire extinguisher. Pressure in tank will stay at 55bar as CO2 is used. Only when all the liquid has gone will the tank pressure start dropping giving you possibly a day before CO2 runs out.


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