How to Clean a Cartridge Filter

If you have a cartridge filter in your pool’s system, from time to time you are going to need to take it out and clean it. But how exactly do you do that?

Not every pool uses a sand filter to clean the water, some pools make use of cartridge filters to remove the dirt, grime and other contaminants in the water. While you may already know how to backwash a sand filter, properly cleaning a cartridge filter is something entirely different. Let’s examine exactly how you remove and properly clean a cartridge filter so you can make sure our pool’s water stays fresh and clean for your friends and family to enjoy.

What Is a Cartridge Filter?

A cartridge filter is, well, exactly what it sounds like. In most cases it is an oval or square cartridge made up of different layers of elements that are designed to trap dirt and grime so they don’t enter into your pool. In a swimming pool, these filters are usually found near the pump. In most pools, the filters are designed to be cleaned and reused multiple times. However, from time to time, you may have to replace one or more of the elements in your filter to ensure that it properly filters the water while it is in use.

Advantages of a Cartridge Filter

The biggest advantage you will find when using a cartridge filter is the frequency you have to clean it. Typical sand filters require you to backwash them to clean them multiple times a month or even more depending on how often you use a pool. A cartridge filter, on the other hand, is designed to only be cleaned approximately four times a year. This, of course, will vary depending on where you live and how much you use your pool.

Clean the Filter

While you may not have to clean a cartridge filter as often as other types of filters, the process can often be more time-consuming. Cleaning the filter is easy to do, but there are many more steps that you have to perform in order to clean it effectively. Let’s examine what you need to do to properly clean a cartridge filter.

  1. Shut off the system. Before you begin, shut off your pool’s pump and go ahead and shut off the power just to be safe.
  2. Remove air from the system. Turn the air relief valve that is usually located on the top of your filter slowly to remove any excess air from the system.
  3. Take off the clamps holding the filter together. Different types of filters use different mechanisms to hold the filter together, these must be removed in order to remove the filter.
  4. Remove the top of the filter. Once the clamps are removed, take off the top of the filter to expose the elements inside of the cartridge.
  5. Slowly and carefully remove each of the elements of the cartridge and set them aside. Take note of how each element is positioned inside the filter and take note of any damage to the elements. If you find any cracks or tears, you should consider replacing those parts of the filter.
  6. Using a degreaser, coat all of the different elements of the filter. Some cleaners require that the elements be soaked overnight while others simply need to be coated and rinsed. Follow the instructions included on your degreaser’s package carefully.
  7. Rinse the elements with a hose gently. If you have a hose attachment designed for pools, consider using those settings for rinsing the elements.
  8. Once all of the elements have been cleaned, return them in the proper order and secure them in place.
  9. While your filter is apart, go ahead and double check the O-ring on the filter tank. If it is dry rotted or appears too flat, you will need to replace it before reassembling your filter. If it appears to be in good shape, add a light layer of silicone based lubricant to the O-ring.
  10. Replace the filter and close the clamps that hold it securely in place.
  11. Turn your system back on and then open the air relief valve to release any excess air that is in the system. Keep the valve open until a steady stream of water sprays from it.
  12. Double check the system pressure to be sure it is in normal range. If the PSI levels seem off, you may have put it back together incorrectly or you may have other problems with your system.


Cartridge filters allow you to go much longer periods of time without having to shut off your system and clean them. In most cases, you only have to clean them about four times each year. Still, the process itself, while easy, is more involved and will take you longer to clean it properly. But, by following the steps we have outlined above, you should be able to get the job done in no time while also performing a good cleaning of the filter so your system runs perfectly and the water stays clean and ready for swimming.

Happy Swimming!

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