You rinsed the filter last month and the pressure is already high again. The hose only moved the easy dirt.
What clogs a filter in South Texas is not leaves. It is sunscreen, body oil, and fine dust baked into the pleats where water pressure cannot reach.
Find out what you have first
Open the tank lid or look at the plumbing. A cartridge filter holds one or more pleated tubes you lift straight out. A sand filter holds sand you cannot see. A DE filter holds fabric grids coated in white powder.
Each one gets cleaned a different way. Using the wrong method is how people ruin a filter in one afternoon.
Shut it down and bleed the pressure
Turn the pump off at the breaker. The timer alone is not enough. Then open the air relief valve on top of the tank and let it hiss until it stops.
A pressurized filter lid can come off hard enough to break bone. Thirty seconds of bleeding the air is worth it.
Cleaning a cartridge filter
Pull the cartridge out and stand it up. Use a garden hose with a straight nozzle, no pressure washer.
Hold the water at an angle so it slides down inside the pleat instead of hitting it head on. Work top to bottom, all the way around, and spread each pleat open with your thumb as you go.
That rinse handles dirt. It does nothing for oil.
Two or three times a season, soak the cartridge overnight in a filter cleaner made for the job. Rinse it again after. The water coming off will be darker than you expect.
Never soak a cartridge in muriatic acid first. Acid sets the oils into the fabric and the cartridge is finished.
Cleaning a sand filter
Sand does not get pulled out and washed. You backwash it, and we cover how to backwash a pool filter step by step.
Once or twice a year, backwashing is not enough. Oils gum the sand grains together into clumps, and water tunnels straight through instead of filtering.
The fix is a sand filter cleaner poured into the skimmer, left to sit overnight, then backwashed out in the morning.
Sand itself lasts five to seven years. After that the grains wear round and stop catching anything.
Cleaning a DE filter
Backwash first to blow the old powder out. Then open the tank and lift the grid assembly.
Hose every grid on both sides until the fabric is white again. Look hard while you do it. A tear the size of a fingernail sends DE powder back into your pool and clouds the water for days.
Set the grids back exactly how they came out, close the tank, then add fresh DE through the skimmer with the pump running.
How often
Deep clean a cartridge every three to four months in season, and rinse it whenever the gauge climbs 8 PSI over clean. Chemically clean sand or DE once or twice a year.
Heavy swim loads change that. A pool full of kids and sunscreen every weekend dirties a filter two or three times faster than one that mostly sits.
Know when to stop cleaning and buy
A clean filter that still runs high pressure is telling you it is done. Look for these.
- Pleats that stay gray after a proper soak.
- Bands cracked or the end caps pulling loose.
- Pleats crushed flat or splayed apart.
- Any tear in a DE grid.
- Sand older than seven years.
Most cartridges last two to three years with real care.
A dying filter costs you in chemicals and in cloudy water. Our page on repair or replace covers how that math works out.
If the water is still cloudy after
A clean filter that does not clear the water means the problem is chemistry, not filtration. Start with what makes pool water cloudy.
Bring us a water sample and we will test it free at the supply store on Navarro.
Or call (361) 575-5821 and we will come clean it for you.
Frequently Asked Questions
How do you clean a pool filter cartridge?
Shut the pump off, bleed the air, and lift the cartridge out. Rinse it with a garden hose held at an angle so the water runs down inside each pleat. Spread the pleats with your thumb as you work around it.
Can I use a pressure washer on a pool filter?
No. The force tears the pleat fabric and drives dirt deeper into it. A standard garden hose nozzle is all you need.
How often should a pool filter be cleaned?
Rinse a cartridge whenever the pressure gauge reads about 8 PSI above clean. Deep soak it in filter cleaner every three to four months during swim season, and more often if the pool gets heavy use.
Why is my filter dirty again so fast?
Sunscreen and body oil are usually the reason. They coat the fabric in a film that a hose cannot remove, so the filter loads up again within weeks. An overnight soak in filter cleaner fixes it.
Can you clean a pool filter with vinegar or bleach?
Neither works well. Vinegar is too weak for the oils, and bleach can weaken the fabric. Use a filter cleaner made for pool cartridges.
When should I replace a pool filter cartridge instead of cleaning it?
Replace it when the pleats stay gray after a proper soak, when the bands crack, or when the pleats are crushed or splayed. Most cartridges last two to three years.
