Eclipse 12 pump/filter loud?

Mine is dead silent.. It did act up once like what you are saying. What I did is take the plastic snapon piece underneath where the long plastic tube is connected going into the tank.. there is a little gear in there.. If it is not seated correctly, it well make alot of noise. It just pops out, wipe it and push it back in. Also be very careful when removing the tanks hood. the lighting mechanics is very senastive. Mine went out the first two weeks.. I rewired it and it working fine now. But the bulb connection is very flimsy and well come undone if the lid is bumbed alot when removing it on and off alot.. km