I heard of a guy who had a small fridge, you know one of those little dorm frides, and he ran a line from his tank that went into the fridge through a bunch of coiled up tube and then back into his tank. Neet idea but I have not had to worry about it my tank is in the family room in the basemnent and it stays at 76-78 with the AC on. I have also heard that having a sump that uses the flex tubing with ridges helps to cool the water as it goes into the sump.. Good luck,
Erik