this is my first try at posting pictures, guess i'm going through a learning curve. to ansewer your questions. my tank is a 70 gl oceanic rr with center overflow, my lights are 2 150 mh (20000k) and a nova extreme t5 . the powerheads are 2 seios 1100 and 2 seios 600, they are going on 2 years, going 24/7. the return is split , coming from my sump via a viva aqua pump rated at 748, so, i'm probally getting 600 @ 4 ft. the brain you see has been with me 4 years and has doubled in size since i bought it