Couple of recommendations, timers for the lights, makes life easier. Your Lfs should sell cooling fans for tanks, figure out which button controls what lighting. (Guessing you have actinic and white light). Mount the fan so it blows on the waters surface (evaporative cooling). And set the fan on a timer to come on at or shortly after the lights come on.
I fought over heating with my 75 for years before I figured out what to do. My big tank stays within 1 degree between day and night (actually gets warmer at night).
I fought over heating with my 75 for years before I figured out what to do. My big tank stays within 1 degree between day and night (actually gets warmer at night).

