http://www.canreef.com/vbulletin/showthread.php?t=53138
What I've done is taken the impeller out, flipped all of the little flaps one way (so they all point in the same direction), wrapped it about 6 times with fishing line (4 lb), and then wove a pattern around them anchored in the middle of the original wrap. Simple and reversible. No glue either, the start of each of the 2 pieces of fishing line is tied and the other end heated with a lighter and stuck to itself.
Check out the link above if you're interested in the pump. I tested it in saltwater and it works great... I actually modded it because it didn't produce very fine bubbles in fresh water
I forgot that saltwater acts differently.