# Automatic CO2 question...



## WaterWorld (May 7, 2006)

Does anyone know of an automatic shut off pressurized CO2 system in the market? I was wondering if there is something out there that can be set to shut off when the lights go out and turn on when the lights go on. All the help and or suggestions will be helpful. Thanks again.


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## jrs (Mar 18, 2006)

That is the purpose of a solenoid. You hook it up to the same timer as your lights and it shuts off at the same time.


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## Fish Dude (Oct 31, 2006)

Yep, jrs is right. If you want a pressurized CO2 system to be automatic, you need to have a regulator that is controlled a solenoid. If it doesn't have a solenoid, you'd have to turn it off and on manually by basically opening or closing your CO2 tank.

A solenoid is essentially an electric valve. When power is supplied to the coil [i.e. solenoid is plugged in], the spring inside the solenoid compresses which causes the seal between the solenoid's o-ring and the gas inlet to be "broken". When the solenoid is no longer powered, the spring expands re-creating the seal and the flow of gas is cut off.

As jrs mentioned, you can plug the solenoid into the timer that controls your lights (assuming you have them on a timer and if you don't you really should) and the CO2 will be released when your lights come on and turned off when the lights turn off.

To take it a step further, you can also use a pH controller in addition to a solenoid and it essentially monitors the pH of your tank and supplies power to your solenoid if the pH in your tank is above the set level and cuts the power off when the pH is at your set-point or below it. In case you were unaware, as you add CO2 to your tank, the pH will go down due to the carbonic acid produced from the CO2.


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