Very creative, I have always wanted to have a pond some day and have looked into several ways of filtering it and the way you have this set up is awesome water intakes from top and bottom I love it!
I have always liked the 3 rain barrel pond filtration with one moving bed and 2 stagnant to filter the water seemed simple to clean just agitate 2 stagnant barrels and drain through the bottom to remove detritus and debris but your setup is definitely top 3 that I have liked for filtering a pond thank you for sharing.
