I have two questions that I need help with. First is I think I need more flow. I have a 65 gal. and right now I am running one powerhead that I believe is 400 gph and the return off my canister filter. Would it be way to much flow if I took out the powerhead ( looks ugly in the tank) and replaced it with a koralia 3 rated at 850 gph? Second question is I am thinking about putting a sump under my tank but I need a return pump. What size of return pump would I need on a aquarium this size? The overflow box is a 600 gph overflow. Once I get the sump set up I would get rid of the canister filter so that flow would be gone. Any help would be wonderful. Again thank you.