# CO2 all day and night?



## Symplicity (Oct 14, 2011)

How many of you shut off your CO2 (timer) to match your photoperiod? Is it a waste to have CO2 on 24x7? Any thoughts out there.


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## Kooka (Feb 8, 2011)

Simple answer is yes, running CO2 in a planted tank when the lights are off is a waste. The CO2 is only utilized by the plants when they are photosynthesizing, and that only happens if there is light.


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## acropora1981 (Aug 21, 2010)

I can't give you a general answer as to how many of us shut off CO2 at night, but I would wager that most ppl who use pressurized CO2 use a solenoid to shut off the gas at night.

Furthermore, the best way to run CO2 is to have it come on about 30-45 minutes before the light comes on, as this way you are at proper CO2 concentration right when the light comes on, instead of having 30-60 minutes of below optimal CO2 concentration. This minimizes the opportunity for problem algae such as BBA to take advantage of low CO2 /high light levels.


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## arinsi (Mar 14, 2010)

don't run co2 at night


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## Yami (May 1, 2011)

i use yeast co2, i keep it on 24/7 yay! no problems so far plants grow really well, fish are happy! but if I could turn it off using a timer i would do that


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## Kooka (Feb 8, 2011)

DIY yeast CO2 produces so little gas that it isn't necessary to turn it off at night. Pressurized CO2 on the other hand can be regulated, and therefore it would be prudent to conserve it and turn it off when the plants are not using it.


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