Pool Filter Cleaning Guide: Sand, Cartridge & DE Filters

Understanding Pool Filter Types

Pool filters remove debris and contaminants through different mechanisms. Each type requires specific cleaning procedures for optimal performance.

Sand Filters (Most Common)

• How they work: Water flows through sand bed, trapping debris
• Pros: Low maintenance, long-lasting, affordable
• Cons: Cannot filter particles smaller than 20-40 microns
• Lifespan: Sand lasts 3-5 years, filter tank 15+ years

Cartridge Filters

• How they work: Pleated fabric filters trap debris and particles
• Pros: Excellent filtration (10-15 microns), no backwashing needed
• Cons: Require regular cleaning, cartridges need replacement
• Lifespan: Cartridges last 3-6 months with proper care

DE (Diatomaceous Earth) Filters

• How they work: DE powder coats grids, filtering particles as small as 2-5 microns
• Pros: Best filtration available, crystal clear water
• Cons: Most maintenance intensive, requires careful handling
• Lifespan: DE powder replaced with each cleaning, grids last 1-2 years

Sand Filter Cleaning

When to Clean Sand Filters

• Pressure gauge reads 8-10 PSI above clean start pressure
• Water flow visibly reduced
• Every 4-6 weeks during peak season
• After heavy storms or algae treatment

Backwashing Procedure

1. Turn off pump and ensure all power is off
2. Set valve to "Backwash" position
3. Start pump and run until sight glass shows clear water (2-3 minutes)
4. Turn off pump and set valve to "Rinse"
5. Run pump for 30 seconds to settle sand bed
6. Turn off pump and return valve to "Filter"
7. Record new baseline pressure for future reference

Deep Cleaning Sand Filters

Every 6 months, use sand filter cleaner to remove oils and built-up debris:

1. Backwash normally first
2. Add sand filter cleaner per manufacturer instructions
3. Set to "Recirculate" and run for 2 hours
4. Turn off pump for 8 hours (overnight works well)
5. Backwash thoroughly until water runs clear
6. Rinse and return to normal filtration

Cartridge Filter Cleaning

Cleaning Schedule

• Weekly inspection: Check for visible debris buildup
• Bi-weekly cleaning: During peak season
• Monthly cleaning: During off-season
• Replacement: Every 3-6 months or when pleats show wear

Basic Cleaning Procedure

1. Turn off pump and relieve system pressure
2. Remove filter housing top (usually twist-off)
3. Carefully lift out cartridges - note their position
4. Initial rinse: Spray with garden hose to remove loose debris
5. Deep clean: Use cartridge cleaner and soft brush
6. Final rinse: Thoroughly rinse until water runs clear
7. Inspect cartridges: Check for tears, worn pleats, or excessive buildup
8. Reinstall cartridges in original positions

Professional Cleaning Tips

• Rotate cartridges: Have two sets and alternate them
• Soak overnight: For heavy buildup, soak in cartridge cleaner overnight
• Brush technique: Brush between pleats at 45-degree angle
• Replace, don't over-clean: Cartridges lose effectiveness when over-cleaned

DE Filter Cleaning

When to Clean DE Filters

• Pressure rises 8-10 PSI above clean start pressure
• Every 4-8 weeks depending on pool usage
• After algae treatment or heavy contamination
• At season opening and closing

Backwashing DE Filters

1. Turn off pump
2. Set valve to "Backwash"
3. Run pump until discharge water is clear (2-4 minutes)
4. Turn off pump and set to "Rinse"
5. Rinse for 30 seconds to settle grids
6. Return to "Filter" position
7. Add fresh DE powder through skimmer (see dosage chart below)

DE Powder Dosage Chart

Deep Cleaning DE Filter Grids

Every 3-4 backwashes, remove and clean the grids manually:

1. Turn off pump and drain filter tank
2. Remove filter head and lift out grid assembly
3. Spray with hose to remove DE and debris
4. Soak in filter cleaner if heavily soiled
5. Inspect grids for tears or damage
6. Reassemble filter and add fresh DE powder

Common Filter Problems and Solutions

Cloudy Water Despite Clean Filter

• Check chemical balance: Poor chemistry affects filtration
• Increase run time: Pool may need more circulation
• Filter too large: Oversized filters can cause channeling
• Dead spots: Improve water circulation with return jet adjustment

Short Time Between Cleanings

• High bather load: More frequent cleaning needed
• Poor water balance: Causes rapid filter loading
• Algae growth: Treat algae first, then clean filter
• Undersized filter: Consider upgrading filter size

High Pressure After Cleaning

• Sand filter: Sand may be channeling or need replacement
• Cartridge filter: Cartridges may be worn out
• DE filter: Grids may be damaged or clogged
• Valve issues: Check for proper valve operation

Filter Maintenance Schedule

Weekly Tasks

• Monitor pressure gauge readings
• Visual inspection of cartridge filters
• Check water clarity and flow rate

Bi-weekly/Monthly Tasks

• Clean cartridge filters
• Backwash sand and DE filters (as needed)
• Test and balance water chemistry

Seasonal Tasks

• Deep clean all filter types
• Replace worn cartridges
• Inspect and replace sand (every 3-5 years)
• Professional filter system inspection

When to Replace Filter Media

Sand Replacement Signs

• Sand is 3-5 years old
• Frequent backwashing needed
• Sand has hardened or clumped
• Water clarity problems persist

Cartridge Replacement Signs

• Pleats are worn or frayed
• Cartridge won't come clean despite soaking
• Fabric appears gray or discolored
• End caps are cracked or damaged

DE Grid Replacement Signs

• Fabric has tears or holes
• Grids are bent or warped
• DE powder passes through into pool
• Grids are 1-2 years old