# DIY CO2 Pressure Problem?



## ericpop27 (May 13, 2008)

*Anyone ever have either of the following problems using DIY CO2?

1) Sometimes the tube fills up with water from the aquarium.
2) Sometimes the bottle gets compressed like all the air is being sucked out, rather than CO2 pressure building up and forcing itself out.

Not sure what is going on with my latest mix here...*


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## CherylH (Jul 22, 2004)

Are you using a check valve? If so, double check to be sure it's facing the right way.


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## ericpop27 (May 13, 2008)

*No, I don't have a check valve. Do I need one?*


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## Seattle_Aquarist (Mar 7, 2008)

Hi Ericpop27,

When I used DIY CO2 I had similar problems. The problem was the fact that I used really warm water when mixing my solution and was connecting it to the aquarium right away. As the liquid cooled, it created a vacuum that allowed water to flow from the tank to the bottle and/or it caused the bottle to "compress". If you are using really warm water to mix up your solution, try waiting overnight, or until the solution is room temperature before connecting to tank.


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## CherylH (Jul 22, 2004)

ericpop27 said:


> *No, I don't have a check valve. Do I need one?*


It's not mandatory, but I'd strongly suggest it.


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## TimboJones (Feb 29, 2008)

I'm sorry but the volume of water does not change because of the change in temp. Its a law of physics. The air in the chamber is what would have done it.


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## YankyTexan (May 7, 2008)

"I'm sorry but the volume of water does not change because of the change in temp. Its a law of physics."

So when someones' water pipes freeze and burst it's not the water it is the air inside the pipe that is the culprit?


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## Seattle_Aquarist (Mar 7, 2008)

TimboJones is partly correct, both water volume and air volume are effected by temperature; both are subject to the laws of Physics.

YankyTexan, you are right, it is the water that causes the pipe to burst. Water volume contracts as it get colder until it reaches the freezing point. Water as a solid (frozen) takes up more volume than the same amount as a liquid.


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## hoppycalif (Apr 7, 2005)

Every liquid I can think of expands with temperature, just as every solid does. When water freezes it expands as it freezes, but if you continue to lower the temperature of the ice I believe it will again contract very slightly, just as other solids do. The amount of expansion of water with temperature is very small, so it rarely has any noticeable effect.

One noticeable effect would show up with global warming. If the average temperature of the world's oceans goes up, sea level would rise, even if no ice melted into the water.


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## ericpop27 (May 13, 2008)

*The check valve did the trick, it's now a steady stream of CO2. No backwash and no bottle shrinkage.*


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