Ok, I am planning on building a pondless cascading waterfall/stream next to my front porch. I have never built a water feature before but I feel I have a good idea about how it needs to be done. It will be about 7-8 feet long and about 3 feet high, with two or three short drops. I am also planning on putting in an auto fill float valve connected to a new zone on my sprinkler system, that way if for some reason the float sticks, I won't flood my yard. My question is this: Do I need to filter the water if there is no pond, and thus no fish? I would think that with the water wouldn't get stagnant since it will be constantly moving. If I am wrong, can I just put some chemicals in the water to keep it clear? Honestly I am just trying to save myself the 200 bucks HD wants for the falls filter.