How to Size an Above Ground Pool Filter

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The standard a/g filter types are 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
Click here to view the above-ground filters. 

Step by Step

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Step 1

Firstly, your pump’s HP is a major key to narrowing the field of filters suitable for your pool. If you need help finding or just want to confirm you have the correct sized pump, check this video’s description for a link to our guide called “How to size an Above Ground Pool Pump
Now we’ll go through each filter type, matching standard pump horsepower with the suggested filter size.

Click here to view above ground pool pumps. 

Step 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

Step 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

Step 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

Step 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.

Click here to view the above-ground filters. 

Comments

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(1 to 25 of 25)

 Posted: 8/29/2021 

When you say a 16" or 18" sand filter, what is measured" What dimension makes the sand filter 16" or 18"?
 Reply

InyoPools Product Specialist  Posted: 9/1/2021 

The diameter of the tank is 16" or 18". Most sand filters will list the tank size in the title or have it stated in the description. You can view the sizes and specifications of our filters here, sand filters section
 Reply

 Posted: 9/1/2021 

Thanks for the reply. I have an older filter that has no labels left on it. I was curious to know what size it is but did not know what to measure. Now I know. Thank you.
 Reply

InyoPools Product Specialist  Posted: 9/1/2021 

Measure the diameter of the tank to figure out the size. Refer to step 2 on this guide, How To Identify the Make and Model of My Pool Filter
 Reply

Anonymous  Posted: 2/21/2021 

I have 33’ round 54” deep pool. So it’s 30,000 gallons of water. What size pump, and filter do I need?
 Reply

InyoPools Product Specialist  Posted: 3/1/2021 

The size of your filter would depend on the type of filter, which is how we break it down in the guide above. What type of filter do you want to install on your 33' round pool?
 Reply

 Posted: 8/30/2020 

I have a 16x32 rectangle on ground pool with a 2 HP pump and a Hayward C751 cartridge filter. and a GPM of 75. I am thinking I need a larger filter and am looking at the C1200 for a 120 GPM. My issue is water flow from my return, does not push water very far and am wondering if the larger filter would help this.
 Reply

InyoPools Product Specialist  Posted: 8/31/2020 

Has this flow issue been a constant problem, or is it something that has recently cropped up? I ask, because if it is a recent problem, it may be a sign that the cartridge is dirty or needs to be replaced. Also, what is the PSI rating on the filter when the pump is running?
 Reply

 Posted: 8/31/2020 

my PSI usually begins between 18-22
 Reply

InyoPools Product Specialist  Posted: 8/31/2020 

When you say "begins," does it spike to a higher pressure after a few minutes? And is this a new problem, or has the pressure been a concern since those two pieces of equipment have been installed?
 Reply

 Posted: 8/31/2020 

my pressure rises gradually as water is filtered quicker when vacuuming but find the need to clean daily
 Reply

InyoPools Product Specialist  Posted: 9/1/2020 

Is this a new problem, or has the pressure been a concern since those two pieces of equipment have been installed?
 Reply

 Posted: 9/1/2020 

It seems since I went to the cartridge (from earth) and new pump I have more water issues, especially algae. Vacuuming more now than ever.
 Reply

InyoPools Product Specialist  Posted: 9/1/2020 

I am leaning towards the filter being too small if the PSI starts that high, and it requires you to clean it every day. I would go with the C1200 to be on the safe side. The C900 would be a half-measure, and likely would not completely fix the problem.
 Reply

 Posted: 9/1/2020 

thank you, 1 more question. What size filter is in the C1200
 Reply

InyoPools Product Specialist  Posted: 9/1/2020 

Cartridge for Hayward C-1200 (PA120)(C-8412) - PL0146
 Reply

Anonymous  Posted: 7/16/2020 

Is there any sand filter for my 10×30. Prism Metal frame pool?
 Reply

InyoPools Product Specialist  Posted: 8/24/2020 

A 16-inch sand filter should be suitable for a pool of that size. For example, Sand Filter with Top Mount Valve 16" Tank
 Reply

 Posted: 6/8/2020 

My above hrs pool is 16x32 4.5 deep what size of pump sand filter I need?
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InyoPools Product Specialist  Posted: 10/20/2020 

From Step two in the article: 15’ X 27’ to 18’ X 33’ - 18-Inch Tank & Up
 Reply

 Posted: 3/7/2020 

12x24x54 oval pool what de size filter do I need
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InyoPools Product Specialist  Posted: 3/9/2020 

In step 4, your pool size is listed.
 Reply

 Posted: 6/19/2019 

What is sand filter do I need for my 30 foot above ground pool
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Anonymous  Posted: 7/9/2019 

15x30 oval above ground 4.5 deep I currently have a 1.0 HP
 Reply

InyoPools Product Specialist  Posted: 6/19/2019 

Refer to step 2 in the guide.
 Reply