Swimming Pool Filters

Swimming Pool Filters for Clear, Healthy Water

At PoolStore, we supply a wide range of swimming pool filters for domestic swimming pools, including sand filters, cartridge filters and replacement multiport valves as well as the correct filter media (sand). Whether you're upgrading your system or replacing an old unit, we have options to suit every pool size and budget.

We also list on this page filters for automatic pool cleaners and pre-filter bags 

How do pool filters work?

The filter is one of the most important pieces of swimming pool equipment. It traps within it particles dirt and debris and returns clean water back to your swimming pool. Inground swimming pools pools and large above ground swimming pools usually have sand filters. These consist of a large cylindrical chamber filled with special filter sand. Pool water is pumped in under pressure at the top and works its way down the filter and leaves at the bottom. On the way through the dirt in the water should be trapped inbetween the particles of sand. Smaller pools usually have a paper cartridge filter. The water is pumped through the filter cartridge and the dirt is trapped by the paper.

How do I clean my filter?

Filters need to cleaned regularly. In the case of sand filters the water must be re-directed up through the sand bed and out to waste. On the way up it flushes out the dirt. This is called back washing. Sand filters come with a valve to change the direction of water flow it is known as the multiport valve. It can be mounted on the side of the filter or on the top. If it is side mounted there is usually a glass dome in top of the filter to view the water. Paper cartridge filters are cleaned by removing them and hoseing them off but they dont last very long so it is important to replace them with new ones regularly.

 What Goes Inside a Pool Sand Filter?

A pool sand filter uses specially graded filter sand designed for swimming pool filtration. Most swimming pool sand filters require 16/30 grade silica filter sand, approximately 0.5–0.8mm grain size.   Never use building sand or play sand in a pool sand filter, as it will not filter correctly and can damage the system. Check the label on your sand filter tank for the correct sand weight (for example, 50kg, 75kg, 100kg, etc.). Using the correct grade and amount of filter sand is essential for proper filtration.

How Do I Change the Sand in My Pool Filter?

Pool filter sand typically needs replacing every 3–5 years, depending on usage and water quality. How to Change Sand in a Pool Sand Filter:

1. Turn off and isolate the pump.
2. Remove the multiport valve or top dome.
3. Inspect and clean the laterals inside the tank.
4. Fill the tank halfway with water (this protects the laterals).
5. Carefully add the correct amount of new filter sand.
6. Reassemble the filter.
7. Backwash thoroughly before returning to normal operation.

Replacing the sand restores proper water flow and improves filtration efficiency.

What Is the Handle on Top of My Sand Filter For?

The handle on top of a pool sand filter is part of the multiport valve. It controls the direction of water flow through the filter. Common settings on a sand filter multiport valve in are:

• Filter – Normal operation
• Backwash – Cleans the sand
• Rinse – Settles the sand after backwashing
• Waste – Drains water from the pool
• Recirculate – Bypasses the sand filter
• Closed – Stops water flow

The multiport valve allows you to maintain and operate your sand filter properly. Always turn off the pump before moving the handle.

Why Buy Swimming Pool Filters from PoolStore?

• Trusted UK supplier
• Wide range of leading brands
• Competitive pricing
• Fast UK delivery
• Expert technical advice

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