Pool Cartridge Filter: When to Clean or Replace

pool vacuum under water in the pool

Pool experts recommend cartridge filters because they make pool maintenance more manageable, and the filters themselves are easier to clean. They are also simple to replace when it’s time to get a new cartridge. What you should remember, however, is when you should clean your cartridge and when you should replace it.

When to Clean Your Pool Filter Cartridge 

It’s not difficult to find out whether your filter cartridge is due for a cleaning. All you have to do is check the pressure on your gauge. When it reaches 8 to 10 pounds per square inch (psi) above the starting pressure, it’s time to clean your filter cartridge. When your cartridge is new, and the psi is 10 when you start the system for the first time, you should replace the cartridge when the psi reaches 18.

That is not the only time to clean your cartridge, however. You should also clean it if you’re applying an algae bloom treatment as part of your pool maintenance. If a major storm hits your area, you should also clean the cartridge after the storm. For public pools, which are used more frequently by more people, cleaning the cartridge at every opening or closing is crucial for keeping the water safe.

How to Clean a Cartridge

You can call a pool cleaning professional to clean or replace your cartridge. But if you want to do it yourself, here’s how to properly clean your cartridge filter:

  • Switch the breaker to the filter pump to off before doing anything else.
  • Relieve the pressure in the filter by releasing the air valve on top.
  • Remove the drain plug, and completely drain the filter.
  • Loosen the locking knob by turning it counterclockwise. Use a wrench to loosen the clamp. Your filter might require a specific socket. Check the literature that might come with the filter to find out which socket it takes.
  • Remove the bolt and the C-clamp.
  • Remove the top of the cartridge filter.
  • Spray the filters with a full-spray nozzle on your garden hose until the filters are clean. Rotate the cartridge to access every side. Don’t use a pressure washer as it might damage the filter.
  • You can use a cartridge cleaner. Soak the cartridge in a bucket containing clean water mixed with cartridge cleaner for up to 24 hours. This will break down the compounds that water alone cannot remove.
  • After soaking the cartridge in your cleaner solution, hose it down to remove the broken-down compounds and the cartridge cleaner solution.
  • Re-install the filter when you are satisfied with the cleaning. Follow your cartridge manufacturer’s instructions for installing a cartridge filter.
  • Tighten the knob.
  • Switch the breaker to the filter pump to “on”.
  • Check the pressure gauge. The recommended pressure level is 8 to 15 psi.
  • If you cannot do this yourself, call a pool repair and cleaning professional.

When to Replace Your Pool Filter Cartridge 

Pool filter cartridges do not last forever, so you’ll have to replace them at some point. But cartridges don’t have a set date for replacement, and different cartridges in different pools don’t “expire” all at the same date. You’ll have to become an expert in determining whether a cartridge is due for replacement.

Band Wear

Some signs point to a need for a new cartridge. One of those has to do with the bands. Some people think those bands are “wear bands” and that a broken band is a sign that the cartridge has failed, and so it needs to be replaced. Those bands do break down at some point, though, so you’ll have to check them each time you clean the cartridge.

Even if you observe significant band breakage, your cartridge might still be in good condition. The bands are there to keep the spacing between the filter pleats consistent. Though the cartridge might still be working when the bands are broken, its ability to filter is reduced.

Cartridge Color and Oils

The color of the cartridge can also tell you about its condition. Although the cartridge will not remain as white as when it was brand new, it should not have oily or dark brown stains. If you do find such stains and oils on the cartridge, it’s a good idea to buy a cartridge cleaning solution. Cartridges might have recommended cleaning solutions. The solution should get rid of the oils and stains.

If you still can’t remove the oils and stains using a good cartridge cleaning solution, your cartridge filter is due for a replacement. If you’re doing a pool repair, you might want to replace your cartridge filter as well.

Filter Pleat Condition 

You don’t have to check each pleat to get a good idea of what the filter’s condition is. Just take a close look at the pleats, and judge if the material is falling apart. It’s not hard to determine whether the material has degraded enough to warrant a replacement. If degradation is obvious, it’s time to replace the cartridge filter.

End Caps

The easiest way to tell if your cartridge filter is due for replacement is by looking at the end caps. If the end caps are already broken, that’s a sign that the filter has reached the end of its lifespan. If you find some stress cracks, your filter is still fine. But if the caps are close to breaking, replace the cartridge as soon as possible.

Cartridge filters have a lifespan of up to five years, maybe a little more. However, they can deteriorate more quickly if they are not cleaned regularly or if the pressure reaches beyond the recommended psi levels. Cleaning them might extend their lifespan, depending on other factors, such as the quality of the water, the amount of debris that falls into the pool, the frequency of pool use, or the presence of spores that might contaminate the pool water.

Talk to us at Pool and Patio Pros if you need guidance with pool cleaning or if you need other pool services, including pool resurfacing.

Give us a call, or text us, at (602) 806-8535 or fill out our contact form to get in touch with us.