I have cracked 2 housings for my Danner 5 over the days. Once was totally me fault as I tightened the fitting too much, and the second occured from lousy nylon braided vinyl tubbing "torquing" the fitting. I can tell you that sealing the housing totally leak proof is damn near impossible once you crack it. Better off to order a replacement. And no, petsmart won't have it, trust me

Personally I am thinking of buying an Ehiem 1048 due to partially this and because I now have to have my rig near my monitor and the Danner just throws out too huge of an EMF. Still Danners ar5e great pumps and these are really the only 2 problems with their design.