bawlsyTDi said:set up a filter system. Get a big rubbermade container or even a trash can would work. Cut a hole in the side of the container/trash can the size of pipe desired. Put in pipe with a 90* elbow, so the pipe exits out the side and up towards the top of the container. Run pipe at least 3/4 the way to the top of the container. Fill with lava rock (the stuff that goes in the bottom of a grill). Top with sponge material. Cut an intake hole in the top of the container and pipe this to about 1/2 way down. Seal the inlet/outlet. Enjoy your new filtered pond.
Ive thought about doing this with my own pond. You have totally inspired me. With an outdoor pond, its not a catastrophe if the filter ends up leaking like it would be indoors. I'm going to try to make a filter myself.