Flow-Through / Waterfall Filter

Flow-through and waterfall filters

Flow-through filters, also called gravity or waterfall filters, sit above the pond's water level. A pump feeds water in, it passes through the filter media and returns to the pond by gravity, often over a stream or waterfall.

Why choose a gravity filter

• Large biological capacity: the open chamber holds plenty of media for bacteria, which suits fish-heavy ponds.
• Easy access: lift the lid to check and clean media.
• Natural look: the return can feed a waterfall or watercourse directly.

Things to plan for

The filter must sit higher than the pond so water can return by gravity. Many people hide it behind rocks or plants at the top of a waterfall. Because water exits at low pressure, a flow-through filter cannot push water further uphill.

Build a complete system

Pair your filter with a filter & watercourse pump, add a UVC clarifier to control green water, and use a spillway for a clean waterfall edge.