"I own the Eheim 2215,and I've used it both on Tropical tanks,and as a 2nd filter on my goldfish tanks,and I love it!!
I like the fact that I can stuff them with so much more filter media,and that filters can be rinsed in old tank water and restored to life again.
I've only had one problem,and that was when my cat was chasing a group of Dojo Loaches in the tank,and somehow managed to loosen a hose.I had 49 gallons of water on my floor,and about 1 gal. in the tank.Since that ,I'm definitely paying a lot more attention,and have made it where that won't happen again.That wasn't any fault of Eheims,just a fat cat who got bored."