How to Size an Above Ground Pool Filter

Here are a/g filter types: Sand, Cartridge, and diatomaceous earth, or DE; these filters operate differently but the method of sizing them is the same. You should consider the following when sizing a new filter:

  • Your current pump’s HP
  • Pool Size
  • Swimmer/Debris load

1. Firstly, your pump’s HP is a major key to narrowing the field of filters suitable for your pool. This guide overviews each filter type helping you to match standard pump horsepower with the suggested filter size.

2. Sand
Round:

  • 8’ to 15’ Round: 14-Inch Tank & Up
  • 15’ to 24’ Round: 16-Inch Tank & Up
  • 24’ to 36’ Round: 18-Inch Tank & Up

Oval:

  • 12’ X 17’ to 12’ X 24’ - 14-Inch Tank & Up
  • 12’ X 24’ to 15’ X 27’ - 16-Inch Tank & Up
  • 15’ X 27’ to 18’ X 33’ - 18-Inch Tank & Up

3. Cartridge
Round:

  • 8’ to 15’ Round:- 50 sq. ft & Up
  • 15’ to 24’ Round - 75 sq. ft & Up
  • 24’ to 36’ Round - 90 sq. ft & up

Oval:

  • 12’ X 17’ to 12’ X 24’ - 50 sq. ft & Up
  • 12’ X 24’ to 15’ X 27’ - 75 sq. ft & Up
  • 15’ X 27’ to 18’ X 33’ - 90 sq. ft & Up

4. DE
Round:

  • 8’ to 24’ Round - 15 sq ft & Up
  • 24’ to 36’ Round - 20 sq ft & Up

Oval:

  • 12’ X 17’ to 15’ X 27’ - 15 sq ft & Up
  • 15’ X 27’ to 18’ X 33’ - 20 sq ft & Up

5. Now we have a window of filter sizes we can consider four pool, let’s think about variables that may cause you to upsize your filter. The larger the filter the longer you can go between cleanings. Oversized filters can hold more dirt without sacrificing flowrate or spiking filter pressure.

  • If you are the party pool in your neighborhood, that means more swimmers and inevitably more dirt. If you don’t want to spend the day after each part doing pool chores.
  • Larger filters also have higher flow rate capacities, this makes for lower back pressure compared to the smaller models. Less backpressure makes for less stress on the pump, filter and plumbing as a whole.

If you have any other questions about pool and spa products please do let us know - we are here to help!

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