Pool Filter Sizing Calculator
Check whether your planned circulation flow fits a filter’s area and published flow limit. This pool filter sizing calculator compares four Pentair Clean & Clear Plus cartridge sizes and includes a custom option for a filter with specifications you enter yourself.
Check flow against a filter’s area and rated limit, then compare four Pentair Clean & Clear Plus sizes.
How to use this calculator
The result considers both the manufacturer flow limit and your chosen design loading per square foot. That helps you see why filter area and GPM must be considered together when comparing equipment, rather than selecting a filter solely by pool gallons.
- Enter the design or peak system flow you need the filter to handle.
- Select a listed cartridge filter or enter a custom filter’s area and rated flow.
- Choose an appropriate design loading and review the limits and size comparison.
Worked example
At 100 GPM, a 320-square-foot filter has a loading of 0.3125 GPM per square foot. With a selected design loading of 0.375 and a published 120 GPM rating, the CCP320 is within both checks. A CCP240’s 90 GPM published limit would be below that same 100 GPM flow.
Example inputs illustrate the calculation. Enter your own measurements, product directions and rates to plan your pool.
Turn your result into a plan
A flow-limit check is a starting point for filter selection. Debris load, cleaning frequency, pressure loss, plumbing connections and service clearance can change the best choice. Verify the maximum pump setting and other system components before ordering.
Explore related equipment
Review these product pages as part of your equipment planning. Confirm model, installation and system compatibility before ordering.
Pentair Clean and Clear Plus 520 Cartridge Filter | 160332
View product details →Frequently asked questions
Can I size a filter using gallons alone?
Pool volume helps establish a circulation goal, but filters must also handle actual flow. Use the turnover and TDH tools to refine GPM before comparing filter area and manufacturer limits.
Why do the CCP420 and CCP520 share a flow limit?
Both have a published 150 GPM flow rating. The CCP520 provides more filter area, which does not automatically authorize a higher flow than the published limit.
Can I enter a sand or DE filter?
Yes, through the custom option, using that exact filter’s area, manufacturer flow limit and permitted design loading. Do not apply a cartridge-filter loading assumption to another filter type.
Does 'within flow limits' guarantee a suitable installation?
No. The result only checks the entered flow and loading assumptions. Confirm installation clearance, pressure limits, plumbing, operating conditions and local requirements separately.
Continue your pool planning
Need help choosing pool equipment?
Send Pool Supply Depot your pool size, calculator results and existing equipment details. We can help review product options and the information to confirm with your installer. Based in Henderson, Nevada, we serve pool owners and pool professionals nationwide.
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