Depends on your intent. I did a 55w on an 80 shallow with 40 Breeder sump to battle a major Dino outbreak that wiped out my sps. Plumbed the pump into the return section and discharge into the overflow section through a filter sock so I would get everything. Dinos were done in 48hrs. I did baste the rocks and kept it in the column at least 2-3 times a day.