When you say huge swings in PH what are you talking? Unless your doing wild Discus I wouldnt worry about the swing unless its really really crazy. Your fish need a small break from the Co2 at night, Especially when the plants arent doing anything with it. Plants only use the Co2 when the light is on. Because the plants arent using it, your basically just wasting the Co2 and stressing the fish more then the PH swing will by not giving them the break from the Co2.Mine is a pressurized CO2 system. I understand the plants do not use CO2 while the lights are off. I started trying to use the same philosophy as you of turning it off with the lights, but my PH started taking some huge swings between "night" and "day". Now I run it 24/7, and have no problem.
yes... thats what im saying is Running Co2 at night Does no good. No reason to do it with a pressurized system.Constevens if I read your post right you are running CO2 durning the day when you lights are on correct. If that is the case then your comment at the start of the post is cunfusing. Did you mean running CO2 at night does no good. If that is the case then I agree. I run my pressurized system so that the CO2 comes on 1 hour after the lights go on and goes off 1 hour before the lights go off. My drop checker usually runs a tad towards yellow, I have tried to turn off the airstone and when I do then about an hour or so after turning it off my fish are at the top of the tank, so I leave it on 24/7. I do get some pearling.