I have two MJ1200's in my 75G Malawi tank providing circulation. The silenced venturi tube with adjustable valve is a great feature, because you can dial in just the right amount of bubbles if you want any. I had a MJ900 in the tank previously that just ran and ran and ran, these units do not jam or stop for anything. I have had that happen with Hagen's in the past, where the impeller just stops and the whole thing gets super hot (luckily it is in water so the windings didn't overheat). They come with many accessories, though the hang-on attachment didn't work for me because my antique tank (slate bottom, metal frame with tar sealing the glass) is too thick around the edges. I used the triple suction cup method, which is not 100% satisfactory, but has held up for several months for me. Overall a great powerhead.