Deep-clean cartridges, but used half the soap?


New member
Apr 8, 2017
Austin, Texas
Hey everyone,

I've been a reader since I bought a house with a pool and discovered this site while learning how to take care of it. First time posting!

So I discovered the cartridge deep-clean procedure here after painstakingly tooth brushing one of my carts trying to get mineralization off of it (the water here is EXCEPTIONALLY hard). All I can say is thank goodness there's a better way!

I soaked all four of my carts in Cascade-water last night, but I only had about 4.5 cups to the approximately 35-40 gallons of water. The water felt really soapy and it dissolved very well, so I didn't go out at midnight to get more and they soaked for at least 10 hours. But now I'm wondering if it's a good idea to proceed with the acid step.

Do you fine fine folks think proceeding will ruin my carts, or do you think I am going to be fine? Is it better safe than sorry and do another soak with the correct amount of dishwasher soap?

Thanks in advance, and thanks for the great website!


TFP Expert
Platinum Supporter
May 23, 2015
Tucson, AZ
I would stay away from soap based products as they will likely leave residues that are hard to remove. The most extensive way to deep clean a cartridge is a two step process.

Step 1 : TSP + Bleach

If you can find it in the big hardware stores (usually in the paint section), TSP (trisodium phosphate) is the best way to clean organic residues. You have to be really careful though as many hardware stores carry products that are labelled "TSP" but often say "alternative" in small letters under it and that is sodium metasilicate; you don't want alternative TSP, you want REAL TSP. The problem is, real TSP was banned from retail consumer cleaning products in the 1970's because it was thought that it contributed to algae blooms. Well, it could, but industrial farm fertilizer run off is a much larger source of phosphates and is the real cause of water fouling, not household detergents. Anyway, that fight was lost because politicians can't understand math much beyond 2+2=4 and have attention spans the size of a peanut, so TSP has become harder to find. In some states, it is simply outlawed from sale. A common brand of TSP is from the manufacturer Savogran.

The formulation to use is 1/4 cup TSP and 1/2 cup of bleach to 1 gallon of water. The bleach can be left out if the cartridges are still in good shape with no visible staining. The TSP forms a very high pH solution and the phosphate component is very good at removing organics and complexing metal ions. You can mix it up in a garbage can lined with trash bags and just soak the cartridges all at once.

DO NOT get the TSP solution on yourself or on anything aluminum. TSP will corrode aluminum.

Step 2 : Muriatic Acid soak

You can then soak each cartridge in a dilute MA mixture. 10:1 (water : acid) should be more than enough or the cartridge manufacturer may have an exact formulation. The MA will remove any calcium scale from the filter media.

You ALWAYS want to do the TSP step BEFORE the MA step, and acid will often react with organics and harden them making it impossible to remove them.


TFP Expert
Apr 19, 2013
Sacramento, CA
Welcome to TFP!!!! :cool:

Out of an abundance of caution I'm going to recommend you redo the soak stage again with the proper amount of dish washing soap. Chem Geek's post asserts that not completing this step adequately may result in damage to the filters once the muriatic acid is applied in the next step so I wouldn't take chances. The psot is a reprint of advice from the manufacturer.

Chem Geek's original Post:

After 7 years, I've replaced my 4 cartridges in my filter (I could have gone longer, but the straps were starting to break and I figured I had a good run with these cartridges). The replacement cartridges for my Jandy CL340 were from Unicel® and they had instructions with them that I thought were helpful and consistent with what we've been telling people -- note the specific instructions for Baquacil/Biguande as well.

Cartridge Cleaning Instructions for Chlorine Users

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 Supplement for Baquacil® Users."

What is the procedure to clean my cartridge?

Remove the cartridge from the filter housing following the manufacturer's instructions.
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.
Rinse until all dirt and debris are gone.
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; or (3) one cup dishwasher detergent to five gallons of water.
Rinse the cartridge again to remove oils and cleaning solution.
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.
Rinse the cartridge clean and reassemble housing.

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 Biguanide 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.

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