Cartridge Filter Use and Care - Further Reading

Cartridge Filters

Cartridge filters capture particles down to 10-15 microns.

How to Clean a Cartridge Filter

Cleaning Tools

Brass Hose Nozzle.jpg
Brass Sweeper nozzle.jpg

Use a garden hose with a gun type nozzle or brass sweeper nozzle.

Special filter cleaning tools can be found at FilterFlosser and AquaComb.

It is not recommended to use a pressure washer to clean a cartridge filter. Unless done extremely carefully at a low pressure, a pressure washer will tend to tear the filter fabric.[1] You also run the risk, if there is too much pressure, of pushing the small particles into the interior of the filter elements.

Normal garden hose pressures are more than sufficient if you use an appropriate nozzle.

There have been mixed reviews of using the Worx Hydroshot for cleaning filters.[2]

Cleaning Tool Comparison

I put the brass nossle, the Filter Flosser, and the AquaComb to the test to clean 4 Hayward cartridges.[3]

The Filter Flosser wasn't worth the effort. It shoots some nice streams, but the added feature of the combs in the AquaComb make it the overall winner.

The AquaComb is better than the brass nozzle because it's a more efficient and cleans a larger area saving both water and time. The brass nozzle delivers a nice hard blast of water, but it has a limited area and takes more time.

The fingers (comb) on the AquaComb make it much easier to get deep into the filter. If you need a little extra blast of power in a smaller area, you can turn the AquaComb sideways and deliver more water vertically. This came in handy a couple of times and worked really well for a final once over.

Overall the brass nozzle does a very good job for the price, but you'll probably spend a bit more in water (for some areas this is an issue). I really liked the AquaComb and its now my tool of choice for cleaning the filters. It was faster, easier and used less water.

Cartridge Cleaning Instructions for Chlorine Users

When should a cartridge element be cleaned?

For swimming pools, clean the cartridge when filter canister pressure reaches 25% above the initial system or new cartridge starting pressure.

For spas, establish a routine cartridge cleaning schedule based on the amount of spa usage. If Baquacil® is used as a sanitizer, the filter element must be cleaned with Baqua Clean® before any cartridge cleaner is used (Step 4). Please refer to "Cartridge Cleaning Supplement for Baquacil® Users."

What is the procedure to clean my cartridge?

  1. Remove the cartridge from the filter housing following the manufacturer's instructions.
  2. Use a garden hose with a straight flow nozzle to wash down the filter element. Work from the top down, holding the nozzle at a 45 degree angle, and wash all the pleats with emphasis between pleats.
  3. Rinse until all dirt and debris are gone.
  4. For all spa cartridges and elements used in swimming pools where perspiration, suntan lotions, and other oils are present, soak the element for at least on hour (overnight is most effective) in (1) a commercial filter cleaner; or (2) one cup trisodium phosphate (TSP) to five gallons water.
  5. Rinse the cartridge again to remove oils and cleaning solution.
  6. If the filter has a coating of alage, calcium carbonate (residue from calcium hypochlorite), iron, or other minerals, soak the cartridge in a solution of one part muriatic acid to twenty parts water until all bubbling stops. WARNING: Failure to remove all oils and cleaning solution before acid soaking will result in a permanent restriction of water flow and cause premature cartridge failure.
  7. Rinse the cartridge clean and reassemble housing.

Don't use acid to clean a filter cartridge without first cleaning with a degreaser like TSP. If there is any grease on the filter, acid will solidify it, quite possibly damaging the cartridge.

A note on dishwasher detergent chemistry - automatic dishwasher detergent hasn't contained TSP (trisodium phosphate) since the 1970's. The EPA all but banned the use of phosphate-based cleaning formulations as they were, unnecessarily, branded as the main cause of eutrophication of waterways (farm runoff is the real source of phosphate pollution in waters). Most dishwasher detergents utilize carbonates and organic surfactants.[4]

You can still purchase TSP as a granular powder in hardware stores (often sold in the paint section) but be careful not to pickup the "eco-friendly" TSP...which is not TSP at all but sodium carbonate (washing soda). Real TSP is banned in some US states though. TSP substitute is pretty worthless IMHO. (it is soda ash and sodium metasilicate) The most common brand sell the real stuff in a red box and the useless stuff in a green box.[5]

Use heavy duty arm length rubber gloves and wear goggles before handling Muriatic acid. Use an over sized plastic container because the neutralizer will take up volume. Put the measured amount of water into the container first MOST IMPORTANT, always add the acid to the water. NEVER add the water to the acid.

Ammonia will also neutralize Muriatic acid. Ammonia will react less violently than baking soda. Additionally, use your pool PH Test to affirm that you have neutralized the acid wash. Look for a PH of 7.0 before you dispose of the solution.

NOTE: Unicel does not recommend the use of diatomaceous earth (DE) with cartridge filters. DE particles will become trapped in the body of the media and shorten cartridge life. If desired, a cellulose fiber (synthetic DE) can be used in moderation.

Cartridge Cleaning Supplement for Baquacil/Biguande Users

What should I know about cleaning my cartridge element if I use a biguanide system such as Leisure time FreeTM or Baquacil®?

Unlike chlorine which oxidizes the bacteria in the water, the active ingredient in biguanide systems, polyhexamethylene biguanide (PHMB), destroys the bacterial cells. PHMB locates and binds to the bacterial surfaces, and then attacks the outer bacterial wall. Once this wall has been compromised, the inner cell membrane (the cytoplasmic membrane) is destroyed. This destruction allows the cell contents to disperse into their surroundings where they are further broken down into their elemental parts by a non-chlorine oxidizer such as Leisure Time BoostTM or Baqua Shock®.

In addition, Leisure Time BoostTM and Baqua Shock® are mild coagulants which combine bacterial cells and other small particles in the environment into particles large enough to be trapped by the filter. The resulting deposit is a gray sticky film on the media which can only be removed with Leisure Time Filter CleanTM or Baqua Clean®. If trisodium phosphate (TSP) or any TSP type cleaner is used prior to stripping the film, the cleaner and the gray film will combine to form a gum-like substance. Once this occurs, the substance cannot be removed from the media and the filter cartridge must be replaced.

WARNING: Follow all manufacturer's instructions, warnings and cautions when using Leisure Time FreeTM or Baquacil® products.

Leisure Time® and Leisure Time FreeTM are registered trademarks of Advantis Technologies, Inc.


  • Use hot glue to glue broken bands back together. If you clean the filter in the morning, by late afternoon on a hot day, they are dry enough to hot glue the bands. You only need the surface of the pleat and the band to be dry and it really doesn't need to be completely dry either.[6]

When to Replace Cartridges?

Cartridges can last quite a while if you take good care of them. Aside from an obvious hole or tear, they can eventually get clogged. A clogged cartridge shows up as the filter pressures starting quite high right after cleaning the cartridge, compared to the filter pressure observed when the cartridge was new.[7]

If after you clean cartridges and get normal filter pressure, and then the pressure rises back up to your "need to clean" pressure within a week or even a couple of days then the cartridge needs to be replaced.[8]

Overnight detergent soak followed by an acid soak never removes everything when cleaning a cartridge. So, physically intact but "well used" cartridges do eventually need to be replaced. However, with proper care this should not happen for a long time.[9]

Note the clean pressure on a new set and every time you clean as well. Just so you can keep track. The clean pressure may rise over time and that is normal wear.