Originally Posted by
bigarn
What kind of lighting do you have? 85 degrees is on the higher side if you have a reef tank, but if it's a steady 85 you should be OK.
This is correct. Stability is the main importance concerning temperature. However, 85 is borderline too high. Once you get to 86 or 87 you will have to be concerned about disease.
I'm highly concerned that this is your temperature before having lighting. The lighting is definately going to raise the temp a degree or two. Do you have glass canopies? Remove those if you can as they hinder gas exchange as well as evaporation (which helps lower temp). A good trick is to position your powerheads to where they agitate the surface of the water vigorously... and to place a fan close to the tank that blows across the water surface.
Your topoffs will increase in volume if you do this, but it will help lower your temp anywhere from 2-4 degrees.
ps-if you have a heater, either unplug it during the day or lower it.