Evaporative cooling worked great! Get the cheap box fans and blow them right on the water. You'd better have a designated RO/DI unit for the make up water though....LOL....I bet I lost 15 gallons per day in the summer with the fan on. One fan kept the water around 84-86 degrees. I never tried 2 fans but I bet you could get it close to 80, but again, have an auto top off.