# Air Pump at night?



## Krishs Bettas (13 Aug 2010)

I  was wondering if it was worth to run a air pump at night because I run my co2 all day and night to help the fish?


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## sanj (13 Aug 2010)

I do. It depnds on how you run your tank. A lot of people into planted tanks tend to be fish load light, but I have a larger number of fish and not running o2 pump overnight led to a horible disaster one hot summer night a five years ago.


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## Iain Sutherland (31 Jul 2011)

+1 that, high fish load needs more care


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## sr20det (31 Jul 2011)

I bought a valve for co2, so it can be switched off at night, yet I do have a high stock level of fish, so would be interested to know if even though the co2 is off, can the fish consume the o2?


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## Sentral (1 Aug 2011)

The thing is when the lights are off the plants will be consuming O2 and so competing with the fish. In light stocking levels this shouldn't be an issue as there should be plenty of O2 from the plants. If you look at amano et al they all use additional aeration a few hours after lights off


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## dw1305 (1 Aug 2011)

Hi all,


> I bought a valve for co2, so it can be switched off at night, yet I do have a high stock level of fish, so would be interested to know if even though the co2 is off, can the fish consume the o2?


Definitely run the air pump, all the bio-load, that is all the living aerobic organisms in both tank and filter *(fish, snails, plants, bacteria) are respiring all the time (using O2, producing CO2). During the light period, it is only when photosynthesis reaches the "compensation point", that the oxygen production from photosynthesis (CO2 in, O2 out) exceeds the plants demand for oxygen (for respiration) and the plants become net oxygen producers.  

A planted tank will have a bigger bio-load (this is not as straight forward as it seems due to the effects plants have on water quality) than an equivalent non-planted tank. If you have lots of fish, or fish with a high O2 demand, you need to run extra aeration at night. If you don't have plants you need to run it all the time.

cheers Darrel


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## Bobtastic (1 Aug 2011)

After reading one of George F's PFK articles (10 planted tank myths) myth #6, I've twisted one of my spray bars so that it causes ripples on the surface so that it drives off excess gas once the Co2 goes off. I previously had very little surface movement and the DC hardly changed colour after lights out/Co2 shutoff. It wasn't a problem b4 as I had no fauna, but since I've added fishies I thought it best.


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