Cartridge filters are the simplest pool filtration technology — no backwash valve, no media to recharge — but cleaning them incorrectly causes premature failure and poor water quality. Most damaged cartridges in the field were killed by pressure washers or returned to service still clogged with oils. Here's the complete protocol.
Record the filter pressure gauge reading immediately after each cleaning — this is your baseline. Clean the cartridge when pressure rises 8–10 PSI above that number. For a typical residential pool with average bather load and moderate debris, that's roughly every 4–6 weeks during the swim season.
Log the post-clean baseline pressure for every cartridge pool account in PoolLens. The next tech to service the pool knows exactly when cleaning is actually due.
Cleaning more frequently than needed actually shortens cartridge life — the pleats need some loading to achieve optimal filtration and constant handling accelerates fabric wear.
Never use a pressure washer on a pool filter cartridge. The high-pressure stream drives debris deeper into the pleat fabric and can blow the end cap bonds apart. A garden hose with a spray nozzle is the correct tool.
Water rinsing removes particulate debris but does nothing for oils, sunscreens, body lotions, and algaecides that bond to the polyester fabric and reduce flow. These deposits cause "blinding" — a cartridge that looks clean but flows poorly and climbs to high pressure quickly after service.
Use a dedicated cartridge filter cleaner (Natural Chemistry Filter Perfect, Leisure Time Filter Clean, or BioGuard Strip Kwik) in these situations:
Soak method: Place the cartridge in a large bucket or trash can filled with enough water to submerge it. Add filter cleaner per label directions (typically 8 oz per 5 gallons). Soak overnight — at least 8 hours. Rinse thoroughly and reinstall.
The most efficient approach for service accounts is to keep a second clean cartridge for each filter type in your truck. When you arrive and pressure is high, swap in the clean cartridge, drive away with the dirty one, and soak it on your own schedule. No downtime for the pool, no rushed rinse, and cartridges get a proper overnight soak rather than a 5-minute hose-off.
| Condition | Action |
|---|---|
| Pleats crushed or matted together | Replace immediately |
| End cap cracked or delaminating | Replace immediately |
| Fabric torn or punctured | Replace immediately — bypass contaminating pool |
| Does not hold pressure between cleanings | Replace — fabric is permanently loaded |
| Mold or permanent staining | Replace |
| In service 2–3 years | Replace proactively at seasonal opening |
Common replacement cartridges: Hayward CX580XRE (C580), Pentair 178584 (Clean & Clear 150), Sta-Rite PRC50. Always verify the exact part number from the filter tank label rather than guessing by size.
PoolLens stores install dates, baseline pressures, and service notes per pool — so you know exactly when each cartridge is due for cleaning or replacement before you arrive.
Open PoolLens Free →Clean a cartridge filter when pressure rises 8–10 PSI above the clean baseline — typically every 4–6 weeks for average residential pools, more often for heavy bather loads or tree debris.
No. A pressure washer forces debris deeper into the pleats and can damage the fabric. Use a garden hose with a spray nozzle at 45 degrees along the pleats.
Replace the cartridge when the pleats are crushed or frayed, the end caps are cracked, it no longer holds pressure between cleanings, or when it has been in service 1–3 years.
Water rinsing is sufficient for routine maintenance. Use a dedicated filter cleaner (soak overnight) quarterly or whenever oils, sunscreen, or body fats have clogged the pleats.