Mine usually ranges between 78 and 82. It's hard to keep the temperature low when I'm running 1200+ watts of metal halides... I don't even use a heater. And that's for 300 gallons of constantly moving water. I would like my temps to be lower (ideally), but there's only so much I can do, short of buying a chiller.
Try to keep your temps within a couple degrees in a 24 hour period. Drastic temp swings are worse for your tank than consistently high or consistently low temps.