I have had a 40 breeder for a few months and coming from having nanos, sumps and plumbing are fairly new to me. I bought a used quiet one 4000(1022 gph) cut back with a valve and have a split return nozzle for my flow. I came across some forums saying to never use your return pump as a primary source of flow and to use Powerheads, is this true? And if it is, why? I have no clue how much flow I have going in my tank I’m just basing it off of if the corals are looking happy or not with the flow they are getting. Below are pictures of my sump layout and return nozzle.