I do have timers. My only set back is the fan plug for my clamp on MH. The internal fan has a seperate plug with a switch. The timer for my lights is a dual plug, which are both hooked to ballasts. The other timer I got is a strip timer w/ four outlets on timer and four outlets on switch. Unfortunately all four plugs are on the same timer. This timer is set to come on when my main lights go off. It is hooked to the light in my sump and an air pump hooked to a limewood airstone inside my skimmer, a little extra nightime skimming. Point is I can't use it or the fan would only come on when the light is off. As I said I have two lights, they are both 150w clamp on MH. The first one I got is older and didn't have the separate plug, the fan kicks on when the light does. I only got this one stupid plug that I got to hook up to come on the same time as the lights. Looks like I got to get another timer!