Cartridge Filters - When to Clean It? When to Replace It?

Using cartridge filters is a great option for pools because they are easy to maintain and simple to clean. Properly maintaining your cartridge filter often comes down to whether to clean the cartridge or replace it.

Check out these expert tips to help you know when each option is appropriate.



When to clean your cartridge filters

The answer to how often you should clean your filter is pretty simple. When the pressure on your gauge reaches 8-10 psi above the standard starting pressure, you should clean the filter.

For example, if you bought brand new filter cartridges, and the first time you started the system the psi was 10, then you would need to clean that filter when the pressure reached 18 psi. Other times you should clean your filter include:

  • During an algae bloom treatment
  • After major storms
  • As part of opening or closing your pool

When to replace your cartridge filters

So when do you replace your filters? There is no expiration date, so it’s important to know signs of a cartridge that needs replacement.

Let’s start with the bands. Contrary to what you may have heard, those bands are not wear bands. This means that the cartridge does not need to be replaced at the first sign of a broken band. However, the bands will break down over time. If you see a significant amount of breakage on the bands, look closely at the cartridge to ensure it is still in good condition. Those bands are specifically designed to ensure proper spacing between the pleats of the filter, so if the bands do break, your filtering ability will be diminished.

Next, look at the coloration of the cartridge. It will never be as white as when you bought it, but it should not have permanent dark brown or oily stains. If it does, that means it is saturated with oils. You need to soak it in a cartridge cleaner to help pull those oils out. If the oils won’t come out with a good cartridge cleaner solution, you may need to replace that cartridge.

PRO TIP: It is not a good idea to use any sort of acid dilution on a filter cartridge.

Now, look between the pleats. You don’t need to check them all, but check enough to get a good understanding of whether or not the material is starting to fray or come apart. If the material is visibly degrading, you should consider replacing that cartridge immediately because you are no longer getting proper filtration.

Lastly, and by far the easiest sign that you need to replace the filter cartridge, is if the end caps are broken. Small stress cracks may not be a problem, but any actual breaks in the cap mean you need to replace that cartridge immediately.


For more information on filter cartridges or any other aspect of pool care, contact or visit your local Leslie's store, or call 1-800-LESLIES.