co2

[One_Trick_Pony]

do i disconnect it at nigth when the lights go off?

or leav it running?

 

[Bloo]

I leave mine running and believe that's the way it "should" be.

 

[One_Trick_Pony]

cheers bloo

 

[Bignose]

There is an issue of lack of oxygen at night... Plants use CO2 during photosynthesis when the lights are on, but when the lights are off, they uptake O2 and expell CO2. Of course, your fish also need O2 to live.

So, during the day the plants are a source of O2 -- very beneficial. During the night, the plants are a sink of O2 in direct competition with the fish's needs.

In addition, the issue is that with the CO2 injection, there may be too much CO2, which can put oyur fish to sleep, permanently. I think the main thing to do would be to peek in on them once during the night and see if they are all hanging out at the top of the tank. If they are all at the top, this is indicative that the rest of the water is oxygen depeted. If they are at all different levels... then there is most likely enough oxygen.