[Funky_Fish14]

I have dual 400W halides, and have an enclose canopy. I also have glass covering my tank. Two 12V fans running while the lights are on prevent them from raising the tank's temp even a degree. I would consider trying this if you can. I think the enclose canopy and only fan openings allows more efficient air circulation for providing fresh/cool air and getting the heat out.

Chris

Edit: I also have no sump, I have a 100gph flow 23g refugium above the tank(sitting directly over the lights too) that needs to be heated during the day sometimes to maintain a proper temperature.