How to Size a Sand Pool Filter

A sand filter can keep your pool water clear.

Your swimming pool should have some sort of filter attached to it that will help keep the water clean so you and your family can enjoy the pool season after season. A sand filter can be a good choice because it requires very little maintenance or cleaning. For example, you typically only need to change the sand inside the filter every three to five years or so. The most difficult part of using a sand filter might be the process of sizing it for your pool.

Step 1

Factor in how many gallons of water your swimming pool holds. If you don't already know how many gallons are in your pool, consult the pool's manual or manufacturer.

Step 2

Check out the size of your pump. The pump size will vary between 0.75 and 2.5 hp; the size is indicated on the side label or in the manual.

Step 3

Use the pool gallons and pump size to choose the right sand filter size. A 3-square-foot sand filter is used for pools with 10,000 to 15,000 gallons of water with pump sizes of 0.75 to 1 hp. A 3.9-square-foot sand filter is used for pools with 20,000 to 25,000 gallons of water and a 1.5-hp pump. A 4.9-square-foot sand filter is used with pools of 30,000 to 35,000 gallons of water and 2-hp pumps, and a 6-square-foot sand filter is used for pools with 40,000 to 45,000 gallons of water and 2.5-hp pumps.

Step 4

Go to your local pool supply store to find the sand filter size you need for your pool.


Double-check the manufacturer’s suggestions for the size swimming pool that the sand filter can handle. The sizes can vary slightly based on model.

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