I have been disappointed in this product since I got it. It doesn't move a lot of water and it's awkward to deal with in the way that it fits in it's "C" shaped holder. I was using Koralia #4's prior to getting the Tunze but both Koralia's failed on me after about six months so I was reluctant to get another Koralia although I really liked their performance. Well, I just finished a water change and about every six weeks or so I take out the powerheads and clean those thoroughly too. When I took the Tunze out of it's C shaped holder, the damn thing (the holder) cracked off. I've got some glue on it now but I am doubtful that it will hold. I guess I'll check out buying another holder but maybe not. I really hate this powerhead.