How to Clean Pool Filter Cartridge - Complete Guide 2024

Tools & Supplies Needed

Find on Amazon: Natural Chemistry Filter Perfect , Replacement Filter Cartridges , Filter Cleaning Bucket

First, Let's Diagnose Your Filter Cartridge Condition

Before jumping into cleaning, examine your cartridge filters to determine what type of cleaning they need. Remove the cartridges from your filter housing and inspect them under good lighting.

Light Cleaning Needed: If you see leaves, debris, and dirt but the pleats are still white or cream-colored, a simple rinse will suffice. The fabric should feel relatively soft and flexible.

Deep Cleaning Required: If the cartridge pleats have turned yellow, brown, or gray, feel stiff, or have visible oil rings around the top, you'll need chemical cleaning. This discoloration indicates oils, lotions, and dissolved organics have penetrated the filter media.

Replacement Time: If the pleats are falling apart, the end caps are cracked, or the cartridge won't come clean even after chemical treatment, it's time for replacement. Most cartridges last 12-18 months with proper care.

Solution 1: Basic Rinse Cleaning (Weekly Maintenance)

For routine maintenance when cartridges aren't heavily soiled:

1. Turn off your pool pump and release pressure from the filter system using the pressure relief valve
2. Remove the cartridge(s) from the filter housing, noting their orientation for reinstallation
3. Use a garden hose with a spray nozzle to rinse from the inside of the cartridge outward, working methodically around each pleat
4. Rotate the cartridge and spray from the outside in, focusing on areas with visible debris buildup
5. Pay special attention to the top and bottom pleats where debris typically accumulates most heavily
6. Reinstall immediately or let air dry if you have spare cartridges to rotate

Pro Tip: Never use a pressure washer on cartridge filters, as the high pressure can damage the delicate filter media and create tears that allow debris to pass through.

Solution 2: Deep Chemical Cleaning (Monthly or As Needed)

When cartridges show signs of oil buildup, discoloration, or reduced flow even after rinsing:

1. Prepare your cleaning solution in a large bucket or trash can. Use either a commercial filter cleaner like Natural Chemistry Filter Perfect or make a solution with 1 cup of trisodium phosphate (TSP) per 5 gallons of water
2. Rinse the cartridges first with your garden hose to remove loose debris
3. Submerge cartridges completely in the cleaning solution, ensuring all pleats are covered
4. Soak for 8-24 hours depending on contamination level. Heavily soiled cartridges may need overnight soaking
5. Remove and rinse thoroughly with clean water, spraying between each pleat to remove all chemical residue
6. Allow to air dry completely before reinstalling, typically 4-6 hours in direct sunlight

Safety Warning: Always wear gloves when handling filter cleaning chemicals and work in a well-ventilated area. Some cleaners contain acids that can irritate skin and eyes.

Solution 3: Troubleshooting Persistent Problems

Problem: Cartridge gets dirty very quickly

This usually indicates poor water chemistry or insufficient sanitization. Test your water and ensure free chlorine levels are appropriate for your cyanuric acid (CYA) level. If CYA is above 50 ppm, you need higher chlorine levels to maintain sanitization. Consider performing a SLAM (Shock Level And Maintain) process if you're dealing with algae or organic contamination.

Problem: Reduced water flow even after cleaning

This suggests the filter media has become permanently clogged with oils and microscopic debris. Try an overnight soak in a stronger degreasing solution, or consider that the cartridge has reached the end of its useful life. Even with perfect maintenance, cartridge filters have limited lifespans.

Problem: Cartridge tears during cleaning

This typically happens when using too much pressure during rinsing or when the filter media has deteriorated with age. Small tears can sometimes be temporarily patched with filter repair tape, but replacement is the best long-term solution.

Cartridge Rotation System for Optimal Performance

Professional pool technicians recommend having two sets of cartridges and rotating them. While one set is in use, the other can be thoroughly cleaned and dried. This system ensures you always have clean, dry cartridges ready for installation and extends the overall life of your filters.

Clean cartridges should be stored in a cool, dry place away from direct sunlight and chemicals. Never store damp cartridges, as this can promote bacterial growth and deterioration of the filter media.

When Chemical Cleaning Isn't Enough

If your cartridges won't come clean despite proper chemical treatment, or if you notice the filter pressure rising quickly after cleaning, the filter media has likely reached its absorption capacity. Modern cartridge filters are designed to trap particles deep within the media, and eventually, this capacity is exhausted.

Replace cartridges when cleaning no longer restores proper flow, when the pleats show physical damage, or when they've been in service for more than 18 months regardless of appearance.