A waterfall filter provides both mechanical and biological filtration for the pond as well as a smooth flow of water to begin the waterfall.
This filter is positioned behind the waterfall of the pond. Water enters the filter (usually from the bottom depending on the design of the particular filter, some enter at the top then fall to the bottom). The water then flows up through the filter material.
The filter material removes medium size particulate from the water column. The filter media also provides a home for beneficial bacteria which break down additional pond waste including fish waste. As the filter fills with water, the water flows over the spillway where it then can cascade down strategically and artistically placed stone to provide a beautiful waterfall and/or stream.
