I have been looking into using natural filtration for my duck pond ( outside of cutting expenses I like the idea of fewer mechanical parts). The most attractive concept I have come across so far is the Mussel. Turns out they can filter through a very large amount of water per day and feed off the detritus etc and polish up the water quite nicely from what I understand. Has anyone used this method and maybe combined with bacteria treatment ? How complicated is it and how well did it work. Currently working on a 6x4x2 pond for 5 ducks. Of course any other ideas or concepts are welcome. I was thinking of adapting a river tank manifold with 2 maxi jet 900 ( 1000gph on circulation mode) to keep water flowing.