i tried to hook up a HOB reef octopuss skimmer (BH-200) i got it running but the flow of my sump was fluctuating. i took out the skimmer and now my overflow box is filling up as well as my display tank and sump is going dry. the tank is pre drilled with a corner overflow 75 gallon tank FOWLR. my display tank and overflow water is at same level. dont know whats wrong or how to fix it. thanks guys....