Pressure gauge is the only real sign of a clogged filter.

Yes, the pressure gauge tells you when to clean it — not how the water looks. You don’t need to guess.

For a cartridge filter, note the pressure when the cartridge is clean. That’s your baseline. Once it climbs 8–10 PSI above that, it’s time to clean. Cloudy water is a late-stage symptom. By then you’re already fighting algae or debris you should have caught earlier.

Cleaning is simple: remove the cartridge, spray it down with a garden hose from top to bottom, nozzle on jet. Work the debris out from between the pleats. No pressure washer — that shreds the fabric. If it’s greasy from sunscreen or body oils, soak for a few hours in a filter cleaner (TSP substitute works fine), then rinse again. Reinstall, bleed air, done.

Replace the cartridge when the pleats start tearing or flattening out. Usually every season or two depending on usage.

Set a reminder to check the gauge monthly during swim season. Future you will thank current you.