This is how I baffled mine, and it works really well:
The sponge is cut from a bigger filter sponge for an Aquaclear filter (like these: http://www.petsmart.com/product/inde...ductId=2754144
), and it's just held on the filter with a rubber band. The water comes out of the filter and then trickles down through the sponge. As long as you make sure the bottom part of the sponge is touching the water, then there will hardly be any current to bother your fish.