Try those pumps they sell in those tacky water fountain things they sell at the drug stores. They work fine, and if you find one on clearance they are only a few bucks, the LFS was selling them for a killer profit in Greensboro, NC. Look for a broken/damaged display fountain and offer them $5 for it, they often will sell it to you, thinking you are a moron for buying a broken piece of junk.
I have had better luck with my micro hang on filter for water movement on my 2.5 gallon - it does not clog up, ever.
The mini pumps from the water fountain things are the only pumps I can keep in my 24 gallon seahorse tank too - all the other minis blow the seahorses all over the place, too much flow.