Cartridge filters work on the "clarification process." They utilize the debris they collect as an aid to improve filtration. As a result, cleaning too often does not allow the filter to work at optimum filtration efficiency, while not cleaning often enough will shorten the life of a cartridge element. So here's a tip.

When you replace the element with a new one, note the start-up pressure on the tank gauge. This reading is the system's total pressure in "pounds per square inch" or psig (gauge). Mark this point with a drop of fingernail polish or a grease pen. Then add 8 pounds to the reading and place another dot. You now have the normal operating pressure for your cartridge in psid (differential). Allow the filter to operate between these two points and clean whenever the gauge reaches the higher pressure mark.

When should a cartridge element be cleaned?

For swimming pools, clean the cartridge when filter canister pressure reaches 8 PSI 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 for Baquacil Users" below.

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 is 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 one hour (over night is most effective) in (1) a commercial filter cleaner; or (2) one cup trisodium phosphate (TSP) to five gallons water; or (3) one cup dishwasher detergent to five gallons of water.

5. Rinse the cartridge again to remove oils and cleaning solution.

6. If the filter has a coating of algae, 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. Click here to learn more about Acid Washing.

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.

WARINNG: Wear rubber gloves and safety glasses when using acid and chlorine. Do not add water to acid. Do not mix chlorine and acid.

NOTE: Most manufacturers do 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.

What should I know about cleaning my cartridge element if I use Baquacil?

Unlike chlorine which oxidizes the bacteria in the water, the active ingredient in Baquacil -polyhexamethylene biqunaide (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 Baqua Shocks, a non-chlorine oxidizer.

In addition, Baquacil is a mild coagulant which combines 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 Baqua Cleans. If trisodiurn 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 Baquacil, Baqua Shock and Baqua Clean.

Unicel and SPP wish to thank thank Zeneca, Inc. for its assistance in compiling this information.
Baquacil^®, Baqua Shocks^®, and Baqua Clean^® are registered trademarks of Zeneca, Inc.