Cleaning a pool cartridge filter is one of the cheapest, highest-impact pieces of pool maintenance. Done monthly, it restores flow, drops filter pressure back to baseline, and extends the cartridge’s life from 2 years to 3 or even 4. Skip it and your pool runs cloudy, your pump labors against high backpressure, and you’ll be buying a $200 cartridge twice as often as you need to.
This tutorial covers a routine hose cleaning and a deeper chemical soak for cartridges that need more than rinsing.
When to clean (not replace)
Hose-clean when filter pressure reads 8–10 PSI above clean baseline, you see lower return-jet flow, or it’s simply been a month. A monthly cadence is the right call for most residential pools during heavy-use season. Chemical-soak once a year, ideally at closing or right before opening.
What you’ll need
- A garden hose with a spray nozzle (not pressure-washer pressure — that destroys pleats)
- A 5-gallon bucket for chemical soaks
- A cartridge cleaning solution OR diluted muriatic acid OR TSP-based detergent
- A new body o-ring — always replace when you open the filter housing
- Silicone pool lubricant
Step-by-step: hose-cleaning a pool cartridge filter
Wait for the pressure gauge to read zero and the hissing to stop completely.
Open the drain plug at the bottom of the filter, then loosen the band clamp or threaded ring at the top. Lift the upper housing off and set it aside on a clean surface.
Hold the cartridge vertical with the open end down. Aim a fan-pattern hose nozzle into the pleats from the top, rotating slowly so water flushes debris down through the pleat valleys and out the bottom. Never spray into the bottom of a pleat — you’ll force gunk deeper into the fabric.
Look for tears, separated pleats, or end caps pulled away from the fabric. If you see any structural damage, the cartridge is done — rinsing won’t bring it back. Time for a fresh element.
If your pool sees heavy bather load, the cartridge picks up suntan oil and body lotion that won’t hose off. Mix 1 cup of TSP (trisodium phosphate) or a commercial cartridge cleaner into a 5-gallon bucket of warm water. Submerge the cartridge for 8–24 hours, then rinse thoroughly.
If your area has hard water, scale forms inside the pleats and won’t come off with detergent. Soak in a 5-gallon bucket of 1:20 muriatic acid to water solution for 5–10 minutes. Always degrease first (TSP) and rinse before acid soaking. Never combine TSP and acid — do them in separate baths.
Rinse the cartridge thoroughly. Replace the body o-ring with a fresh one, lubricate with silicone pool lubricant, drop the cartridge back in, and reinstall the top housing.
Turn the pump on with the air-relief valve still open. Water will spit out as the filter fills and purges air. Once you see a steady stream of water with no bubbles, close the valve. Note the new clean pressure baseline.
If cleaning isn’t restoring pressure
If your filter still runs at high pressure after a complete clean (hose rinse + degrease + acid soak), the cartridge fibers are blinded with absorbed grease the chemicals can’t reach. That’s the “done” signal — time for a fresh element:
Jandy CS100 SF Cartridge Kit
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Jandy CS150 SF Cartridge Kit
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Jandy CS200 SF Cartridge Kit
Shop NowBuy two; rotate them
If you find yourself hose-cleaning every two weeks, buy a second cartridge. Pull the dirty one, drop in the clean one, and let the dirty one soak in TSP overnight without taking the pool offline. Rotating two cartridges roughly doubles the life of each, since they spend half their time recovering between cleans instead of running at maximum load continuously.
If you’re unsure which cartridge matches your filter, send PST Pool Supplies a photo of the old cartridge or the filter housing label. We’ll match the right SKU so your next clean ends with a working pool, not a wrong-size order.