Swimming Pool Supplies & Parts
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StaRite Great White
Unicel Replacement Cartridge For the
Posi-Flo II Ptm 50
Posi-Flo T-50TXR, T-50TX, 50TXR, 50TX
SC3SR50 Unicel Cartridge
Filter Tank O-ring for the SC3SR50 Posi Flo Filter
31935-0001 / O-419
Aladdin replacement O-ring only
Unicel 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 normal system or new
cartridge starting pressure. If Baquacil is used as a sanitizer, the filter element must be cleaned with Baqua Clean before
any cartridge cleaner is used.
What is the procedure to clean my cartridge?
1. Remove the cartridge from the filter housing following the manufactures instruction.
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. If the filter has a coating of algae, calcium carbonate, iron, or other minerals, soak the cartridge in a solution of one
muriatic acid to twenty parts water until all bubbling stops.
Warning: Use rubber gloves and safety glasses when using acid and chlorine. Do not add water to acid.
Do not mix acid and chlorine.
5. Rince the cartridge clean and reassemble housing.
REPLACING A CARTRIDGE FILTER
Q. How can I tell when a cartridge filter element needs to be replaced?
A. With no moving parts or electrical switches to fail, cartridge elements do not have a defined termination point. Instead the fine interstices of the media matrix gradually plug up over time. In a typical spa, the culprit that plugs the media is perspiration and body oils combined with soaps, chemicals and very fine particulate. In a swimming pool, the loading is primarily debris along with sun tan lotions and organic matter such as algae.
Assuming the filter is properly maintained and correctly sized to the pump, determining when the cartridge is exhausted depends primarily on three factors: 1) Shorter cycle time between cleanings; 2) Low water flow rate and high differential pressure; and 3) Catastrophic failure such as a tear in the media or center core collapse. All three are dependent upon proper pool or spa water chemistry and following a routine maintenance schedule. Homeowners should be reminded that filter elements are plastic and should be handled and maintained accordingly.
To maximize the life of a cartridge I suggest:
• Clean the elements per cleaning instructions.
• Never use a stiff brush to scrub the media.
• Maintain pool or spa water chemistry in proper balance.
• Do not allow the differential pressure to go over 8 psi between cleanings.
• Alternate two sets of cartridges when cleaning.
• Use an enzyme treatment to break
Q. Support Bands - why are they put on some cartridges and not others?
A. The bands you see on swimming pool cartridges are added to prevent pleat flutter caused by turbulence inside the canister during the filtration cycle. In addition, bands maintain pleat spacing and make cartridge cleaning and maintenance easier.
Skim filters used in spas rarely require bands. This is because the water flow through the element is under less pressure and is more laminar. Furthermore, the generally smaller size of cartridge used in skim filters can actually make separating the pleats for cleaning more difficult if held firmly in place by a band.
What if the band breaks or comes off? On a well-made cartridge, the bands are carefully adhered to the outer edge of the pleat knuckle and rarely come loose or break in normal use. However, acid soaking or rough handling can cause the bands to break and, in some instances, even separate from the element. A split band - even if broken in several places - will not affect the filtration performance of the element and is not considered a cause to warranty the cartridge. Loose or missing bands is often a sign that the cartridge is worn out and can be a good indication that it's time to replace the element.
Here's a quick tip! When buying a new filter, place your
between the pleats and under the band to check for adhesion. The band
should be firmly attached and not separate easily.