Zach, don't forget to consider the humidity of your local area. Cooling fans lose there cooling ability the higher the humidity. When the inside humidity at my house gets over about 30-35 per cent my cooling fans have more difficulty keeping my temps under control, and I also run my a/c set at 77 degrees F. This is on a 200 gallon system. when i was running a 28 gallon system in the same room, I had to use a chiller to keep tank temps stable, temp fluctuations on the 28 gallon with chiller were kept at 1 to 2 degrees, while on the 200 gallons system and fans only 1 degree fluctuations, but again with the house a/c on. I live in Las Vegas so most humidity is low, you have heard it before, it's a dry heat. Both tanks had a target temp of 76 degrees F, and the fans are on a controller.