I have a total of 6 tanks up and running. A 65 gallon showtank FOWLR, 46 gallon bow front FOWLR, 55 gallon african cichlid tank, 38 gallon community tank (getting ready to change it to something else-- don't know what yet), 20 gallon saltwater guppy and mollie breeding tank (FOWLR) and a 5 gallon NANO reef tank at the office. This thing is addictive!!!!!