I have a quite one 4000 in my sump which pumps about 1000 gph. I also have a wave maker on the side about 200 gph. I do have an algae problem at the time being. I was asking if it is recommended to vacuum the substrate when doing a water change. I have heard conflicting stories. My tank is a 75 gallon. With a 20 gallon sump. In my tank I have a long tenticle anenome, a green top cauliflower coral, some yellow polyps and a bunch of different mushrooms. Fish wise only a sailfin tang, a hippo tang and an engineer goby, also about 10 turbo snails,10 hermits and a green methrith crab. Recently had an anenome that died in my tank and things got out of control. Still trying to recover.