Do Cartridge Pool Filters Need Backwashing? Complete Guide

Tools & Supplies Needed

Find on Amazon: Pool Cartridge Filter Cleaner , Replacement Pool Filter Cartridges

Quick Answer

No, cartridge pool filters do not need to be backwashed. Unlike sand and DE filters, cartridge filters are cleaned by physically removing the filter cartridges and washing them with water or soaking them in cleaning solution. Backwashing is a process that only applies to sand and diatomaceous earth (DE) filters.

How Cartridge Filters Work Differently

Understanding why cartridge filters don't backwash requires knowing how they operate compared to other filter types. Cartridge filters use pleated polyester fabric or paper elements to trap debris and contaminants. The water flows through these pleated surfaces, which physically capture particles down to 10-15 microns (exact filtration capability varies by cartridge - consult manufacturer specifications).

Sand and DE filters, on the other hand, use a bed of sand or DE powder as the filtering medium. When these become dirty, water flow can be reversed through the filter to flush out trapped debris - this is backwashing. Since cartridge filters use replaceable elements rather than a filterable medium, this reverse-flow cleaning method doesn't apply.

Proper Cartridge Filter Maintenance Steps

Here's how to properly maintain your cartridge filter system:

1. Turn off the pump and close any valves leading to the filter housing to prevent water flow during maintenance.
2. Release pressure from the system using the air relief valve on top of the filter housing. This is a critical safety step.
3. Remove the filter housing lid by loosening the clamp band or unscrewing the lid, depending on your filter model.
4. Lift out the cartridge elements carefully, noting their orientation for proper reinstallation.
5. Rinse each cartridge with a garden hose using moderate pressure. Start at the top and work your way down, spraying between the pleats to remove trapped debris.
6. Rotate the cartridge as you spray to ensure you clean all surfaces thoroughly. Pay special attention to areas that appear heavily soiled.
7. For deep cleaning, soak cartridges in a cartridge cleaner solution or a mixture of one part muriatic acid to ten parts water (WARNING: Always wear protective eyewear, gloves, and ensure adequate ventilation when handling muriatic acid. Always add acid to water, never water to acid. Have emergency water available for spills).
8. Rinse thoroughly after any chemical cleaning to remove all cleaning solution residue.
9. Reinstall the clean cartridges in the same orientation they were removed, ensuring they seat properly in the filter housing.
10. Replace the housing lid and secure it properly before restarting the pump.

When to Clean Cartridge Filters

Monitor your filter pressure gauge to determine when cleaning is needed. When the pressure rises 8-10 PSI above the clean starting pressure (consult your filter manual for manufacturer-specific recommendations), it's time to clean your cartridges. For most pools, this typically occurs every 2-4 weeks during swimming season (actual frequency varies by pool usage and conditions), depending on bather load, environmental factors, and water chemistry maintenance.

Having a spare set of cartridges allows you to rotate them - install the clean set while thoroughly cleaning and drying the dirty set. This rotation system ensures optimal filtration and extends cartridge life.

Deep Cleaning Methods

Regular hosing removes surface debris, but periodic deep cleaning removes oils, lotions, and mineral deposits that can clog the filter fabric. Commercial cartridge cleaners are specifically formulated for this purpose and are safer than harsh chemicals.

For stubborn buildup, you can use a diluted muriatic acid solution (always add acid to water, never water to acid). Soak cartridges for 15-20 minutes (follow manufacturer recommendations for soaking times), then rinse thoroughly. Always wear protective equipment when handling acids and ensure adequate ventilation.

Alternatively, a solution of automatic dishwasher detergent and water can help remove oils and organic buildup. Use about one cup of detergent per five gallons of water (ratios may vary - consult cleaning product instructions) and soak overnight.

When to Replace Cartridge Elements

Even with proper cleaning, cartridge elements eventually wear out. Replace them when:

• The pleated fabric begins to fray or develop tears
• The cartridge won't come clean despite thorough cleaning efforts
• The time between cleanings becomes very short (weekly or less)
• The cartridge elements show significant discoloration that won't rinse away

Quality cartridge elements may last 6-12 months with proper maintenance, though this varies significantly based on usage and environmental conditions.

Comparing Filter Types

If you're wondering whether cartridge filtration is right for your pool, consider that each filter type has distinct advantages. Cartridge filters provide excellent filtration without the need for backwashing, which conserves water. They're also easier to maintain for many pool owners since the cleaning process is straightforward and doesn't require valve manipulation.

Sand filters require backwashing but need less frequent attention between cleanings. DE filters provide the finest filtration but require more complex maintenance procedures. The choice often comes down to personal preference, local water conditions, and maintenance comfort level.

Troubleshooting Common Issues

If your cartridge filter system seems to require frequent cleaning, several factors might be contributing. Poor water chemistry can cause premature filter clogging, so maintain proper sanitizer levels and pH balance. High bather loads introduce more contaminants, requiring more frequent filter maintenance.

Ensure your pool's circulation system runs adequately - typically 8-12 hours daily during swimming season (consult your pool system manual for recommended circulation times). Insufficient circulation means the filter can't keep up with contaminant removal, leading to faster clogging and more frequent cleaning cycles.