Try setting your heater to 78 degrees and do the same tracking to see what happens. My tank has the heater set there, the 150 Sunpod, open top, back chambers open and never goes over 81 degrees. Even in the summer. I have some good turbulence on the top of the water also from the return nozzle.
Oh yeah I also have the Bio Cube skimmer, two Korallia Nano's, and a Rio 6hf for the return pump.
Oh yeah again and the Azoo Galaxy light on the fuge chamber.