Pond Box Filters

Choosing the right box filter

Choosing the right model depends on your pond size, stocking levels, and the recommended flow rate of the filter. Make sure your pump is compatible with the filter and provides a suitable flow. Another aspect to consider is the media capacity, maintenance requirements, and whether your pond would benefit from a UV clarifier.

For help choosing the right filtration system, try reading our guide here.

Why choose Swell UK?

At Swell UK, we provide:

• A large selection of filters from leading brands
• Price match guarantee on selected products (see T&Cs)
• Reliable and fast UK shipping, with next-day delivery options
• Expert advice from our pond specialists

Frequently Asked Questions

How does a box filter work?

A pump moves water into the box, where it passes through mechanical and biological media before being returned to the pond. Units that feature a UV clarifier can control suspended algae and green water.

What is the difference between a box and pressurised filter?

Box filters are installed outside the pond and use gravity to return the water to the pond. They usually have a larger media capacity and are easy to access for maintenance. Pressurised filters are sealed units that keep water under pressure, making them ideal for waterfalls.

Do box filters need a pump?

A pump is required to move water from the pond into the filter. Always make sure the pump's flow rate is compatible with the filter's recommended range.

Can box filters clear green water?

Models that feature a built-in UV clarifier can help to control green water caused by suspended algae. The UV light damages the algae cells, allowing them to clump and be removed by the filter.