It's kind of unnofficial cause guiness wasn't at my house... But I (was) planning on using a mag7 as a sump return pump.. It was so loud my neighbor came over within 10 minutes and asked what the loud piece of... ... machinery... was in my house. No I'm not joking. This must be the loudest possible piece of gear ever sold for home aquarium... and the walls aren't that thin either. Functionally it was working fine, but as loud as a aircraft carrier flight deck... TOTALLY unnacceptable. And I VERY HIGHLY recommend taking a pass on these pumps when any of you are in the market for one.