how to size a pool filter


Author: Poolking - Swimming Pool Equipment Manufacturer

How to Size a Pool Filter

Having a pool in your backyard can be an amazing addition to your home. It provides a way to stay cool during hot summer months and a place to entertain family and friends. But maintaining a pool requires some effort and investment in equipment. One essential piece of equipment that you need to properly maintain your pool is a pool filter. However, selecting the right size of pool filter can be a daunting task. In this article, we will discuss how to size a pool filter, so you can make an informed decision when it comes to maintaining your pool.

Why Pool Filters Are Important

Pool water becomes dirty over time due to leaves, dirt, and other debris being carried by winds or rainfalls. These debris are too small to be removed with a pool net, and they can quickly accumulate at the bottom of the pool. A pool filter works to remove these debris and maintain the cleanliness and clarity of the pool. It helps to maintain a safe environment, and it also helps to extend the lifespan of other pool equipment, such as the pump, heater, or chlorinator.

Determining the Right Size of Pool Filter

There are several factors that can impact the decision on the right size of pool filter for your pool. Here are some important things to consider:

1. Pool Size

The size of your pool is a critical factor in determining the size of the pool filter you need. The larger the pool, the larger the pool filter required to effectively filter the water. There is a general rule of thumb that recommends selecting a pool filter that can process the entire volume of the pool water within eight hours. To determine the volume of your pool water, record the length, width, and depth of the pool and multiply them together. For example, if your pool is 15 feet by 30 feet and has an average depth of 5 feet, the total volume of water is 2,250 cubic feet.

2. Pump Size

The size of your pool pump also plays a role in determining the size of your pool filter. The pump circulates the pool water and pushes it through the filter to remove debris. A pool filter should be able to handle the flow rate of the pump. If the pool filter is too small, the water will flow too quickly through it, and it will not have a chance to catch the debris. If the pool filter is too large, the pump may not be strong enough to push the water through it. It is recommended that the pool filter be sized to match the pump and that both are properly sized to match the pool.

3. Type of Filter

There are three types of pool filters: sand, cartridge, and diatomaceous earth (DE). Each type of pool filter has different pros and cons, and the size of the filter should be based on the pool size and pump size.

- Sand filters are the most common type of pool filter. They are cost-effective and easy to maintain, but they may not be the best option for larger pools.

- Cartridge filters require less maintenance than sand filters and can filter out smaller debris, but they can be more expensive.

- DE filters are the most effective at filtering out small particles, but they are also the most expensive and require more maintenance.

4. Maintenance

It is important to consider how often the pool filter will need to be maintained, based on its size and capacity. A larger filter may require less frequent cleaning, but it may be more difficult to access or require more effort to disassemble and clean.

5. Budget

Finally, your budget is an important factor to consider when selecting a pool filter. Larger filters and more efficient filter types are usually more expensive than smaller and less efficient options. However, investing in a quality pool filter can save you money in the long run by reducing the need to replace other pool equipment or to buy expensive pool chemicals.


Maintaining a pool can be a lot of work, but selecting the right size of pool filter can make it easier and more enjoyable. The size of a pool filter depends on several factors, including the pool size, pump size, type of filter, maintenance requirements, and budget. Taking these factors into consideration will help you select a pool filter that is the right size for your pool and your budget.


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