How to Clean a Pool or Hot Tub Filter Cartridge

A filter cartridge is pleated fabric wrapped around a plastic core, and how you treat that fabric decides whether it lasts one season or three. Cleaning isn’t complicated, but a couple of common shortcuts do real damage, and once the media is torn there’s no getting it back. The short version: a garden-hose rinse every month or two, an overnight soak in filter cleaner every few months, and never a pressure washer. Here’s each step in detail.

The routine rinse

Shut the pump off and, on a pool filter, open the air relief valve to bleed the pressure before you open the tank. Pull the cartridge out and take it to a hose. Hold the nozzle at about a 45-degree angle so the water sweeps debris out of the pleats instead of driving it deeper, and work from the top down, rotating the cartridge as you go so you get into every fold. Spread the pleats gently with your fingers where they’re packed. That’s it. A rinse takes five minutes.

How often depends on the water. A hot tub cartridge wants a rinse about monthly. A pool cartridge is happy every couple of months, or whenever the pressure climbs 8 to 10 psi over its clean reading.

The deep soak

Rinsing gets the leaves and grit, but it doesn’t touch the oils, lotions, and mineral scale that slowly clog the media from the inside. Every few months, or at every hot tub water change, give the cartridge an overnight soak in a dedicated filter cleaner mixed to the strength on the bottle. Soak it, then rinse it thoroughly until the water runs clear and there’s no slick feel left, because leftover cleaner will foam in the tub. If your cartridge has a closed or solid end cap, stand it up to dry so you’re not sealing moisture inside the core.

The nicest trick here is to keep a second cartridge on the shelf. When one needs a deep soak, drop the spare in and let the first one sit overnight. The tub or pool never stops filtering, and you’re never tempted to cut the soak short.

Two shortcuts that quietly wreck cartridges

The pressure washer is the big one. It feels efficient, and it will absolutely blast a cartridge clean, along with tearing the pleats and driving holes through the media. Once that fabric is torn, unfiltered water runs straight through the gap and the cartridge is finished. Use a regular hose and ordinary pressure.

The dishwasher is the other one people swear by and shouldn’t. The heat can warp the plastic end caps, and dishwasher detergent leaves a residue that foams and is a pain to rinse out. Skip the bleach too. It breaks down the media fibers over time and shortens the cartridge’s life for a short-term look of clean. A soak in actual filter cleaner does the job without any of that. Plain white vinegar is fine for dissolving mineral scale, but it won’t cut the body oils, so it’s a supplement, not a replacement for a real cleaner.

When cleaning stops working

At some point a soak won’t bring the pressure back down, or the pleats stay grey and stiff no matter what. That’s the media telling you it’s spent, and no amount of cleaning brings it back. That’s the moment to replace the cartridge rather than keep fighting it.

Need a replacement or a spare to rotate? Find your cartridge and its cross-references.