a couple weeks ago we had a really hot week, in the 90's. wat i did, this was in my sw, and i needed my lights on, is i froze a couple of bottles of water, and put one in my tank, and it dropped the temp about 5 degrees. but make sure u have many frozen becos they melt fast. have a couple on hand and get a rotation going. the fan method is good, but if u need your lights on, try the ice.