How do I determine the correct size filter for my pond?
Begin by calculating your pond’s volume (length × width × average depth). Most filters should process the total volume at least once per hour. For example, a 2,000 L pond needs a filter rated at ~2,000 L/h.
If you have koi (which produce more waste), aim for more frequent turnover - ideally every hour.
What types of pond filters are available and how do I choose the right one?
Pond filters fall into several key categories, each suited for different setups and needs:
Pressurized Filters: Enclosed units that maintain pump pressure, ideal when you want to hide the filter or locate it away from the pond edge. They’re easy to maintain but offer quicker water flow, which may reduce filtration time.
Box (Flow-Through) Filters: Open systems that allow slower water flow for improved sedimentation. Best positioned at water level since they rely on gravity to return water to the pond.
Koi & Multi-Chamber Filters: Advanced box filters (such as Nexus models) designed for heavy bioload ponds, especially koi ponds.
Internal / Submersible Filters: Installed inside the pond; compact and unobtrusive but can be harder to access for maintenance.
Gravity-Fed & Pump-Fed Filters: External setups positioned above or level with water—some use gravity to return water; others rely on pump power.
Match the filter type to your pond’s size, stocking level, and aesthetics. Pressured units suit hidden installations; box or koi filters deliver better filtration for heavily stocked ponds.
What is “head height” and why does it matter for my pump selection?
Head height refers to the vertical distance water must be lifted, plus the equivalent resistance caused by pipe friction or length. As head height increases, flow decreases. For instance, a pump rated 1000 GPH at 0 ft head might only yield 500 GPH at 10 ft. To size for a waterfall, multiply the width of the spillover (in inches) by 100–200 GPH per inch at your required head height
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