when i turn the lights+co2 on during the day, fish will start acting weird. they arent gasping for air but just not as active. co2 is at 30ppm(greenish yellow on the drop checker). algae is not my problem, my fish are. with the number of fish i have in there around 20 small-medium size fish, i dont use ferts anymore. i have to stress this that my fish ARE NOT gasping for air when the lights+CO2 are on, they just dont move too much. BUT even though i have surface agitation, they start gasping for air at night time when the lights and CO2 are OFF! they recover quickly once i put a airstone in there.
-i probably have too much CO2 during my photoperiod.
-my plants are taking in too much O2 at night. leaving nothing for fish.