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How to Clean Your Pool's Cartridge Filter

Clean, clear, healthy, safe…these are all words we like to associate with water. Not only do we want our drinking water to be clean, clear, healthy, and safe—we want the same for our pool water, too. One of the most important factors in keeping your pool water beautiful is the pool filter. Many pool owners use cartridge filters, which are effective and easy to maintain. To get the most from your filter, it's important to know how to clean a cartridge pool filter.

Cartridge filters use a cylindrical fan-folded polyester cartridge as the water filtering medium. Water flows through the fabric and traps debris. Cartridges can last 3-4 years before needing to be replaced, depending on pool usage, water chemistry, and maintenance practices. The best way to prolong the lifespan of your filter cartridges is to clean them regularly.

Depending on manufacturer recommendations, you should clean your cartridge filters when either of these situations arise:

Leslie's Pressure Gauge

The filter pressure gauge reading goes up 8-10 PSI above the clean starting pressure.

Leslie's Calendar

It has been 3-6 months since the last time you cleaned your filter cartridges.

Now on to the main attraction. Here are the steps for cleaning your cartridge filter, as well as the tools and supplies needed:

How to Clean a Cartridge Pool Filter

Cleaning a cartridge pool filter is relatively easy. The process consists of pulling out the cartridges, cleaning them, and putting them back in. But there are a few steps to follow to make sure it’s done right. Ready? Ready.

Tools and Supplies Needed:

  • Garden hose
  • Spray nozzle
  • Filter cleaner
  • Large bucket (if needed)
  • Teflon- or silicone-based lubricant

  • Replacement filter tank O-ring (if needed)
  • Replacement filter cartridges (if needed)
  • Rubber mallet (for multi-element filters)
  • Owner’s manual (just in case)

DIY TIP: Be sure to keep all necessary supplies on hand so you’re always ready to clean your cartridge filter as soon as you notice it’s not working properly.

Steps for Cleaning a Cartridge Pool Filter:

  1. Turn off your pool pump at the breaker.
  2. Remove air from the system by slowly opening the air-relief valve (usually located on top of the filter) to remove any excess air from the system.
  3. Remove the clamp or assembly holding the filter together. Your owner’s manual might come in handy here.
  4. Remove the top of the filter.
  5. Slowly and carefully remove the cartridges and set them aside. Inspect everything for damage and wear. If you find any cracks or tears, or if a cartridge is mushy, it’s time to replace the cartridge.
  6. Clean the cartridge using a spray nozzle on your garden hose — spray at an angle to get between the pleats. Never use a pressure washer; it will damage the cartridges.
  7. If the cartridge is really dirty, use a filter cleaner. Follow the manufacturer’s instructions.
  8. If the cartridge is really, really dirty, soak it in filter cleaner overnight. Use a five-gallon bucket or clean plastic trash can, and make sure the cartridges are completely submerged in the water and cleaner mixture.
  9. Next, check the filter tank O-ring on the filter tank. If it’s in good shape, lightly apply some lubricant to keep it that way. If it’s dry-rotted, deformed, stretched, or appears worn out, replace it.
  10. Rinse the cartridges thoroughly.
  11. Return the cartridges to the filter and secure them in place.
  12. Replace the filter top and tighten the clamp or assembly. You may need to tap the clamp with a rubber mallet while tightening to ensure it is sealed properly.
  13. Make sure your air-relief valve is still open to release any excess air in the system. Turn the system back on. Keep the valve open until a steady stream of water sprays from it, then close.
  14. Check the system pressure to ensure it’s in normal range. If the pounds per square inch (PSI) is off, you may have put the filter back together incorrectly, or something else may be wrong with the system. Troubleshoot the pool filter to identify and correct the problem.

SAFETY TIP: Always wear recommended/required safety equipment and follow manufacturer’s recommendations for filter cleaning, maintenance, and proper operation.

If you have any questions or need further tips and direction for cleaning your pool’s cartridge filter, stop by and get advice from the team of experts at your nearest Leslie’s.

Recommended Products

Leslie's Cartridge Cleaner

Cartridge Cleaner

Filter cleaner tool

Cleaner Nozzle

pool filter cartridge

Filter Cartridge

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Leslie’s makes every effort to provide accurate recommendations based upon current ANSI/APSP/ICC-5 2011 (R2022) standards, but codes and regulations change, and Leslie’s assumes no liability for any omissions or errors in this article or the outcome of any project. You must always exercise reasonable caution, carefully read the label on all products, follow all product directions, follow any current codes and regulations that may apply, and consult with a licensed professional if in doubt about any procedures. Leslie’s assumes no legal responsibility for your reliance or interpretation of the data contained herein, and makes no representations or warranties of any kind concerning the quality, safety, or suitability of the information, whether express or implied, including, without limitation, any implied warranties of merchantability or fitness for a particular purpose.