I rested mine on a folded piece of fleece. It seems to have done the trick, but if the vibrations move it just a fraction of an inch, there it goes again! @Callistra, I'll have to check. It came second hand with my ten gallons, and it's fairly old by the look of it.
EDIT: It's an older model of the Hagen Elite 801, called the Elite 80. It is powerful and nearly completely silent if it's not touching something. I often forget to unplug it because I don't hear it running! I bet the newer models are even better.
Last edited by Neight; 12-09-2012 at 02:37 PM.
Reason: Added information