about 4-5 months. i have 2 ac 110's, 2 150w marine stealth heaters, 1 penguin 550 powerhead, the light is 2x65w and all i use is 2 capfuls of flourish when i do my waterchanges no c02 but would like to look into that. i had to get rid of the balas they were becoming aggressive and wouldnt stop chasing eachother and other fish