Im having a problem keeping a constant temp in my tank with my lights on during the day. At night with the lights off my tank stays at 76. During the day with the lights on it climbs up to 80. I know how bad this is and cant seem to fix it. I have tried using a fan on the waters surface but it cools too much at night. I was thinking of setting up a small fan for the waters surface on a timer to come on with the MH lights. My tank is a 75 with a decent sized sump. The lights are PFO 250 x 2 SE mogul with 96 x 2 pc blues. The light itself stays nice and cool due to two 4 inch fans one drawing air in and one pushing it out the other end. any suggestions?