Yeah both are about the same noise wise, I was hoping that they would sort themselves out but if not.. Yep I am going to strip down the impeller system clean and lube etc and check all the hoses. Then on Monday I am going to get some soundproof plaster board and make a box around the filter units to deaden any sound. It's a ball ache but this is my dream tank and I refuse to have fun fun ruined lol