Right beside the sump, on the right, is a 1/3 hp chiller. It was driven by a Mag 5 (500 gph) in the sump. With the T5's and all the pumps, never needed a heater initially. But the chiller ran a lot.
Also in this pic, on the right, is my DIY carbon/gfo reactor which I added later. It is just an old Ro canister set that I converted by enlarging the ports to 3/8 lines to increase flow. The first canister is just a pre-filter, the 2nd for carbon, and the 3rd has GFO.