If your planning for a reef w/ animals that like low to moderate flow, having a total system turnover in the area of 15-20 times an hour should suffice. That means your equipment GPH
added together should be 15-20 times that of the volume of the tank. More demanding corals, such as SPS
corals, will need more flow. There are some variables such as the amount and lay out of the LR
used that will affect the flow in the tank (more rock= more impeded/blocked flow). Those numbers are just a general starting point.