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

Cartridge filters are great for pools as they are easy to maintain and simple to clean. All you really need to know to properly maintain your cartridge filter is when to clean the cartridge or when to replace it.

The question of how often you should clean your filter is pretty simple. When the pressure on your gauge reaches 8 to 10 psi above the 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. There may also be other circumstances you should clean your filter such as: during an algae bloom treatment, major storms or as part of your opening or closing.

Now, when do you replace them? There is no set expiry date on your cartridge, so it’s important to know the telltale signs of a cartridge in need of 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, take a close look 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 should not have permanent dark brown or oily stains. If it does, that means it is saturated with oils and 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. 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.
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Have a question or idea for a future Pro Tips episode? Submit your comments and feedback to [email protected] today!