How to Clean a Cartridge Pool Filter Without Damaging It
A cartridge filter should be cleaned when pressure and flow show it is loaded, not simply because a calendar date arrives. Correct cleaning restores circulation without tearing the pleats or shortening the cartridge life.
Signs the cartridge needs attention
- Filter pressure has risen above its normal clean reading.
- Return flow is weaker.
- The chlorinator reports low flow.
- The pool stays cloudy because filtration is restricted.
- The pump works harder or loses prime.
How to clean it safely
- Switch the pump off and isolate power.
- Release pressure using the filter air relief as directed by the manufacturer.
- Confirm the gauge reads zero before opening the tank.
- Remove the cartridge carefully and inspect the housing.
- Rinse from the top down, working between every pleat.
- Use a proper cartridge cleaning solution when oils or scale remain.
- Rinse fully, reinstall correctly and secure the tank clamp.
- Restart, bleed trapped air and inspect for leaks.
Why a pressure washer is a bad idea
Concentrated pressure can tear the fabric and force debris deeper into the pleats. Use a garden hose with controlled pressure and a nozzle designed for filter cleaning.
When rinsing is not enough
Sunscreen, body oils and scale can remain after a quick rinse. Use the treatment recommended for the cartridge and water condition. Do not mix cleaning chemicals, and never combine an acid treatment with an oily cartridge before degreasing it properly.
When to replace the cartridge
Replace it when pleats are torn or flattened, end caps are cracked, bands are broken or pressure rises quickly after a thorough clean. A cartridge that looks stained can still work, so use condition and performance rather than colour alone.
Check the tank and seal
Clean the sealing surfaces, inspect the large tank seal and make sure the clamp is fitted exactly as the manufacturer specifies. A pressurised filter is not the place for improvised repairs.
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