I wan't to try setting up a external bio filter for my waterfall and rain system. Has anyone done this? If so what is the most effient way to do so. I have a fluval canister filter that i thought would drive the water and then add a skimmer simaliar to one in a salt water tank. I ran 3/8" line which tee's off to pick up the pond and one under the raised bottom to pick up the rain water and possible overflow. I don't know if the pics will show very well, but any input will help.