How can I tell when a cartridge filter element needs to be replaced?

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 hot tub or spa, the culprit that plugs the media is perspiration and body oils combined with soaps, chemicals and very fine particulate.  Assuming the filter has been 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
3. Catastrophic failure such as a tear in the media or center core collapse

All three are dependent upon proper spa water chemistry and following a routine maintenance schedule. Tub owners should be reminded that filter elements are plastic and should be handled and maintained accordingly.

All of the following will help maximize the life & performance of a filter cartridge:

• Clean the elements per cleaning instructions.
• Never use a stiff brush to scrub the media.
• Maintain 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.