I just made a water filter using sand and natural wood charcoal (no chemicals) and two 5 gal buckets. It is Awesome! I assume a pvc pipe would make a nice filter too. You would need to have a fabric over one end and than layer sand and charcoal repeatedly a few times with fabric on the other end. The best fabric to use is hemp because it has a natural anti-fungi benefit. I hope this helps and sorry if it doesn't.
-CMJones