That is what i'm doing with my reef tank. I have 2 fans running on both ends of the lamps. What happened is I made a mistake. I was eager to buy a ballast that would power up 4 bulbs for my planted discus tank. Then I realized that it might be too bright for the fish and the noise from the fan was annoying. I would prefer to not overdrive the lamps because I want to keep the bulbs as long as possible. For my corals I switch bulbs at once a year. I don't want to do that for my plants. Does anyone have any experience with workhorse 7 ballast?