[drumminfish]

I never disconnected my CO2 at night, some people say you should because the CO2 isn't getting used because the plants aren't photosynthesizing without light...some people say the CO2 buildup isn't bad...I guess you can try it, and if your fish start gasping at the top of the tank by morning, then you should turn it off. I left mine on overnight for 2 years, though, and never had any fish die from CO2 poisoning....I guess it just depends on your tank.

Haha at least you didn't ask her if they had any "bongs" at work...