In a previous guide we went through the pros and cons of each main type of pond filter. With your choice made, pond filter installation is next. 

How to install a box filter

Box filters work via gravity so they need to be placed above the pond. For ground-level ponds, the box should be placed at the edge of the pond, with the outlet projecting over so the filtered water drops back into the pond. 

If you have a waterfall, either keep the filter box on the edge of the pond and use a separate, second pond pump, “T” off the filter feed and send one hose up to the waterfall, or place the box at the top, behind the waterfall. 

Place the box on a strong, level surface, where you can easily get to it for maintenance. Outlet pipes on box filters should only be extended with caution, and most are better left short, as the manufacturer intended. Don’t be tempted to reduce the diameter of the outlet pipe, run flexi hose off it, or run it uphill, as the box will likely flood. 

If the placement of a box filter is inconvenient or unsightly then a pressurised filter may well be for you. But big box filters are better pond filtration for Koi ponds because of their much larger filter media capacity.

How to install a pond pressure filter

Of all the pond filtration available, Pressurised filters have the most flexible fitting options. They can be buried in the ground up to their lids or placed a long way away from a pond or waterfall, behind a tree or in a shed. This makes them especially useful when a waterfall is required but you don’t want the filter to be seen or spoil the natural look that you’ve created.

Decide if you want to bury the unit or not and if you do, use a spade to dig a hole and place it in it. If you don’t want to bury it place where you would like it and run the inlet hose from the pond pump in the pond to the inlet on the filter. And then hose from the filter outlet either to the top of a waterfall, via water features or back to the pond. If it comes with a built-in UV light to tackle green water, make sure the cable is long enough to reach a power point. 

Some pressurised pond filters also have a third outlet to flush waste away. This can be left bare, with dirty pond water jetting a short distance into the garden when flushed, or a garden hose can be connected to take the water to a drain or a flowerbed.

How to install an All-In-One pond filter 

All-In-One filters are the quickest and easiest of all filters to install as they are just one device - a pond pump and biological filter combined into one unit - which you place in the garden pond. If you want to use the fountain facility then place the submersible pump at a depth where the fountainhead sticks up a few inches out of the water. Fountains need the pump to be level if they are to produce an even rose of water. If the pond bottom is uneven consider a model with an angle adjustable fountainhead for perfect levelling. 

Tie some string to the filter so that you can retrieve it without pulling the power cable, then place the filter in the pond.   

Swell UK recommend that all garden ponds which contain fish should be filtered with a suitably sized pond filter. Filter media inside the filter colonise with beneficial bacteria, breaking down fish waste, converting toxic ammonia and keeping fish healthy. They have the benefit of clearing the water too so you can view your fish in crystal clear water year round.