Filter Cartridge Tips & Info

Filter Cartridge Tips & Info


The following information is presented so you can better maintain your filter cartridges, help your filter system run at peak efficiency, spend less time on this chore and save money!

How Do I Know When My Cartridge Needs Cleaning?

Here's an easy way to help you determine when it's time to clean your filter cartridge. If dirt or debris is cycled back into your swimming pool, that's a good sign your filter needs attention. As you may know, cartridge filters work on a process known as "clarification." In essence, cartridges use the debris they collect to help improve filtration of your pool water. This means that cleaning too often doesn't allow your filter system to work at optimum filtration efficiency. On the other hand, not cleaning often enough will shorten the life of a cartridge element.

A more technical and precise way to know is, the next time you replace the element, take note of the start-up pressure on the tank gauge. This reading represents the system's total pressure in "pounds per square inch" or PSIG (gauge). Mark this point using a permanent marker, drop of fingernail polish or a grease pencil. Then, add 8 pounds of pressure to the reading and mark that location on the tank gauge, too. You now have the normal operating pressure range for your cartridge in PSID (differential). If you allow your filter system to operate between these two points, and clean your filter cartridge whenever the gauge reaches the higher pressure mark, you are helping your system work at optimal levels & getting the maximum use from each element.

Cleaning Instructions for Pools that Sanitize with Chlorine

For Pools, clean your cartridge when the pressure in the filter canister reaches 8 PSI above the initial system (or new cartridge) starting pressure marked (see above). For spas and hot tubs, establish a routine cartridge cleaning schedule based on how often & how much you use your Spa.

What are the Specific Steps for Cleaning my Filter Cartridge?

  • First, remove the cartridge from the filter housing, making sure to follow manufacturer's instructions.
  • Next, take a garden hose with a straight flow nozzle, and use it to wash down the filter element. Work from the top down, and hold the nozzle at a 45-degree angle. Wash all pleats thoroughly, focusing most on the areas between the pleats. Continue to clean / rinse until all dirt & debris is removed.

More Information for all Chlorine-Treated Spas, & Chlorine-Treated Pools with Heavy Swimmer Load

Note that for ALL spa cartridges, as well as for elements used in swimming pools with heavy swimmer waste (perspiration, lotions and other oils), we recommend that you soak the element for at least one hour (of overnight if possible) using a solution of:

  • Any commercially available Filter Cleaner
  • 1 Cup of Trisodium phosphate (TSP) to five gallons water, or
  • 1 Cup dishwasher detergent to five gallons of water

After soaking, rinse the cartridge thoroughly to remove oils & debris, as well as the cleaning solution itself.

For Cartridge Filters with Algae, Calcium Carbonate & Other Mineral Problems

If your filter element has a coating of algae, calcium carbonate (residue from calcium hypochlorite), iron or other minerals, we suggest you soak the cartridge in a solution of 1 part muriatic acid to 20 parts water, until all bubbling stops. Then, rinse the cartridge clean & reassemble the housing.


  • If you fail to remove all oils & cleaning solution before acid washing, you will permanently restrict the water flow & cause premature cartridge failure.
  • Wear rubber gloves & safety goggles when using acid & chlorine, as these are harsh chemicals that can be damaging to the eyes & skin.
  • NEVER add water to acid.
  • NEVER mix chlorine & acid.

NOTE: Most manufacturers do not recommend that Diatomaceous Earth (DE) be used with cartridge filters. DE particles can easily become trapped in the body of the media, which will shorten cartridge life. If desired, a cellulose fiber (synthetic DE) can be used in moderation as an alternative.

Cleaning Instructions for Pools that Sanitize with Biguanide-Based Products

Chlorine sanitizes your pool or spa water by oxidizing the bacteria in the water. By contrast, the active ingredient in Biguanide-based sanitizers is Polyhexamethylene Biquanide (PHMB) - which destroys bacteria cells. PHMB locates and binds to bacterial surfaces, & then attacks the outer bacterial wall which destroys the inner cell membrane (cytoplasmic membrane). This allows the contents of the cells to disperse, where they are then further broken down into their elemental parts by your non-chlorine oxidizer.

In addition, Biguanide has a mild coagulant property which combines bacterial cells & debris into particles which are large enough to be trapped by the filter. The resulting deposit on the media is a gray sticky film on the media. If you use Biguanide as a sanitizer, the filter element should be cleaned / stripped of this film before a cartridge cleaner is used. We recommend using Filter Perfect (a natural enzyme formula) before continuing with the cleaning process. If trisodiurn phosphate (TSP) or any TSP-type cleaner is used before you remove this gray sticky film, the gray film will combine with the cleaning product to form a gum-like substance that cannot be removed, meaning your filter cartridge must be replaced.

Once you have stripped the film from your filter cartridge, you may continue cleaning using the steps for Chlorine-treated Pools & Spas above.

What does the term "Plumbed backwards" mean?

Simply put, waterlines that attach to the "inlet" and "outlet" on the filter canister were reversed during installation. In this case, the water flow through the filter element will be from the "Inside-out" rather than the "outside-in" (as the filter was intended). Debris rapidly accumulates on the inside of the pleats, water flow is restricted, and the cartridge begins to expand. Eventually, the cartridge's end cap will split, releasing the internal pressure. The filter element is now being by-passed in the filtration cycle.

How can you tell if your system is plumbed backwards?

  • Is the nature of the split in the end cap similar to this?
  • Peel back the broken top and examine the pleats. Is there dirt accumulation on the inside of the pleat pack?
  • Does the support band on the outside of the cartridge, if present, appear stretched and wrinkled?
  • Do the outside of the pleats appear rounded and puffy?

If you are still not sure if your filter is plumbed backwards, shut down the entire system and completely bleed the canister pressure. Remove the cartridge and with the lid off quickly turn the pump on and off. Observe which port is delivering the feed water and assure that it is the "inlet."

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