My 75 has a power head in each corner. I have a emperor 400 for water circulation, using no media and a aqua c remora skimmer w/mag drive 3 pump. Have only 5 fish 1 yellow tang, 1 coral beauty, 1 yellowtail damsel and 2 clownfish. SG is 1.025, pH 8.0, kh 8.0, phosphates 0, nitrates 0.