Sorry I forgot to answer that. Its a 55 gal with 2 about 10 gal wet drys hooked together as a sump/refuge. I have a mag 9.5 as my return. Witch always was to much for my 2 overflows. But I think with the plumbing I put just enough head for it now so I dont have to throttle it back anymore. Each nozzle has about as much flow as a water hose. So good flow but not to much for the fish to swim past it.