Well, more like 7 hours left from say 4 p.m. to 11 p.m. and 7 hours right from 6 p.m. to 1 a.m. That way, you'll have a total photo period of 9 hours. You can play around with that depending on how long you want to light your tank. Keep all your high light requiring corals in the middle of the tank so they get the maximum exposure.