Maintaining a swimming pool involves a variety of tasks, from monitoring chemical levels to cleaning the surface and walls. One of the most critical components of effective pool maintenance is the proper care of the pool filter. There are three main types of pool filters: sand, diatomaceous earth (DE), and cartridge filters. While sand and DE filters require a process known as backwashing to clean the media, many pool owners wonder: do cartridge pool filters need to be backwashed?
In short, the answer is no. Cartridge pool filters do not require backwashing. Unlike sand and DE filters, which reverse the flow of water to flush out trapped debris, cartridge filters have a different cleaning mechanism. However, understanding why they don’t need backwashing and how to properly maintain them is essential for keeping your pool water clean and your system running efficiently. Let’s dive deeper into the mechanics of cartridge pool filters, their maintenance needs, and how they compare to other filter types.
What Is a Cartridge Pool Filter?
Cartridge pool filters operate by using a large, porous filter element made of materials like polyester or paper. Water flows through this element, and the tiny pores trap dirt, dust, oils, and other contaminants, allowing only clean water to return to the pool. Cartridge filters are commonly favored for their compact size, energy efficiency, and superior ability to capture fine particles.
Key Components of a Cartridge Pool Filter System
- Filter housing: The outer casing that holds the cartridge element.
- Cartridge element: The core component that captures debris from the water.
- O-ring: Seals the tank lid to prevent leaks.
- Pressure gauge: Indicates when the filter needs cleaning.
Cartridge filters don’t use sand or DE powder as a filtering medium, so the need to backwash simply doesn’t apply. Instead, they rely on regular manual cleaning and periodic replacement of the cartridge element.
Why Cartridge Pool Filters Don’t Need Backwashing
Backwashing is a cleaning process most commonly used with sand and DE filters. By reversing the water flow through the tank, filters can expel trapped debris into a waste line. This process requires a multiport valve and a significant amount of water, making it less eco-friendly and more demanding on the pool’s water balance.
Since cartridge filters do not use a granular media, they cannot be backwashed. In fact, attempting to backwash a cartridge filter would be ineffective and could damage the system. Instead, maintenance for cartridge filters focuses on manual removal and cleaning of the filter element. This method allows for more efficient cleaning and less water waste.
Efficiency and Water Conservation
One of the biggest advantages of not backwashing is water conservation. A typical backwash cycle can use anywhere from 150 to 500 gallons of water, depending on the size of the filter and the duration of the backwash. In contrast, cleaning a cartridge filter only requires a hose spray and possibly a cleaning solution—dramatically reducing water use and environmental impact.
Energy and Cost Savings
Cartridge filters operate using lower pressure and, therefore, require a less powerful pump to circulate water through the system. This contributes to lower energy usage over time, reducing electrical costs compared to sand or DE systems that need higher flow rates and periodic backwashing.
How to Properly Clean a Cartridge Pool Filter
Though they’re not backwashed, cartridge pool filters still require regular cleaning to ensure optimal performance. A dirty or clogged filter will lead to reduced water flow, increased pressure, and poor water clarity. Here’s a step-by-step guide to cleaning a cartridge pool filter element effectively.
Step 1: Turn Off the Pump
Before opening the filter tank, always shut off the pool pump at the circuit breaker to prevent injury or damage. This is crucial for safety and system integrity.
Step 2: Open the Filter Tank
Use a proper filter tank wrench to open the lid and carefully remove the cartridge element. Set it aside on a clean, flat surface for cleaning. Be cautious when lifting the element to prevent tearing or damage.
Step 3: Rinse with a Hose
Use a garden hose with a spray nozzle to rinse the cartridge thoroughly, starting from the top and working your way down. Spray between the pleats where debris often accumulates. This initial rinse removes the bulk of visible dirt and dust.
Step 4: Soak in Filter Cleaner
For deeper cleaning, soak the filter cartridge overnight in a filter cleaning solution. This step helps to dissolve oils, lotions, and fine particles that normal rinsing won’t remove. Always use cleaners designed specifically for pool filters and avoid harsh chemicals, which can damage the filter media.
Step 5: Final Rinse and Drying
After soaking, give the cartridge a final rinse to remove any remaining cleaner or debris. Allow the element to air dry completely before reinstalling it. A dry cartridge prevents mold growth and ensures longevity.
Step 6: Inspect and Replace O-Ring
Before reassembling the filter tank, inspect and lubricate the O-ring with a suitable pool-grade lubricant. Replace it if it shows signs of aging, cracking, or wear.
Step 7: Reinstall and Restart the System
Place the clean, dry cartridge back into the filter housing, secure the lid, and restart the pump system. Monitor the pressure gauge to ensure it reads within normal operating range.
How Often Should You Clean a Cartridge Filter?
The frequency of cleaning depends on several factors, including pool usage, environmental conditions, and the size of the filter. Generally, it’s recommended to manually clean the cartridge every 2–6 weeks. Here’s a breakdown of influencing factors:
Pool Usage and Bather Load
Highly used pools accumulate more contaminants like sweat, sunscreen, and oils, which can clog a filter much faster. In commercial or public pools, weekly cleanings might be necessary.
Environmental Conditions
Pools in areas with high pollen, dust, or nearby trees and vegetation require more frequent cleaning due to additional organic matter entering the water.
Seasonal Impacts
During the peak swimming season (typically spring and summer), pools operate longer daily cycles, placing more strain on the filter. Cleaning frequency should increase accordingly.
Signs That Your Cartridge Filter Needs Cleaning
It’s not always easy to know when it’s time to clean your filter, but there are several indicators that signal it’s due:
- High pressure readings: A pressure gauge significantly above normal operating levels indicates a clogged filter.
- Cloudy water: Reduced filtration efficiency can’t keep up with debris and contaminants.
- Decreased water flow: If the water returning to the pool is slower than usual, a dirty filter could be the cause.
When to Replace the Cartridge Element
While regular cleaning is essential, even the most well-maintained cartridge elements have a finite lifespan. Over time, pleats can tear, calcium scale can build up, and fabric breakdown occurs. Most quality cartridges last between 1 to 3 years, depending on the model, usage, and cleaning routine.
Signs of a Failing Filter Cartridge
| Sign | Description |
|---|---|
| Torn or frayed pleats | Physical damage compromises filtration. |
| Chalky buildup | Indicates calcium scaling, which is hard to remove and affects flow. |
| Repeated high pressure | If the filter stays at high pressure even after cleaning, it may be worn out. |
| Old age | If the cartridge has reached its expected lifespan (generally 1–3 years), replace it. |
Comparison: Cartridge, Sand, and DE Filters
Understanding how different filter types work helps pool owners make informed decisions. Here’s a concise comparison:
Filtration Efficiency
| Filter Type | Micron Rating | Performance Comment |
|——————|—————|———————-|
| Sand Filter | 20–40 microns | Best for larger debris, less effective for fine particles |
| DE Filter | 2–5 microns | Most efficient, but requires frequent backwashing and DE powder refilling |
| Cartridge Filter | 10–20 microns | Offers good efficiency without needing backwashing |
Cartridge filters fall in the middle regarding micron filtration size, making them suitable for most residential pool applications.
Maintenance Requirements
Sand filters require periodic backwashing and occasional media replacement. DE filters require frequent backwashing and regularly adding DE powder. Cartridge filters, on the other hand, require only periodic manual cleaning and element replacement—no backwashing needed.
Best Practices for Cartridge Pool Filter Maintenance
To maximize filter life and pool water quality, adhere to these expert-recommended practices:
Rinse After Each Use (Optional but Helpful)
Quick rinsing of the cartridge after every few days of operation, especially during heavy use or high pollution, can help prevent clogging and prolong the time between thorough cleanings.
Use a Filter Cleaner Monthly
For deep cleaning, use a commercial pool filter cleaner once a month to break down oils, metals, and fine particles trapped in the pleats.
Monitor Filter Pressure Regularly
A pressure gauge is the best indicator of when the filter needs cleaning. Mark your “clean pressure” and clean the filter when it rises by about 8–10 psi above that level.
Store Cartridge Properly When Off-Season
During the off-season or pool shutdown, remove the cartridge, clean it thoroughly, and store it in a dry, protected area to avoid mold and mildew buildup.
Use a Filter Lubricant on O-Rings
Lubricating the lid’s O-ring with a special silicone-based lubricant guarantees a good seal and prevents wear.
Common Misconceptions About Cartridge Filters
Despite their popularity, some myths continue to circulate about cartridge pool filters:
Myth 1: “Backwashing Removes More Debris”
In reality, backwashing is suited only for sand or DE media and doesn’t apply to cartridge filters. Cartridge filters can capture finer particles when cleaned properly and regularly.
Myth 2: “Cartridges Last Forever”
All filter cartridges degrade over time and must be replaced. Failure to replace them when needed can result in poor water quality and system strain.
Myth 3: “All Cartridge Filters Are the Same”
Cartridge filters vary dramatically in pleat design, surface area, and material quality. Higher-quality cartridges with more pleated surface area provide better filtration and longer life.
Environmental and Economic Benefits of Cartridge Filters
Because they do not require backwashing, cartridge filters are an ecological and economical choice for many pool owners. They conserve water by needing only a simple rinse and avoid the frequent disposal of sand or DE media associated with their counterparts.
Moreover, they don’t require large amounts of electricity to function under pressure, adding to cost savings over time. The lack of backwash waste also means no disruption to local drain fields or septic systems, making them ideal for environmentally conscious pool maintenance.
Conclusion: Do Cartridge Pool Filters Need to Be Backwashed?
No, cartridge pool filters do not need to be backwashed. Instead, proper maintenance involves periodic removal and cleaning of the filter cartridge using a garden hose, appropriate filter cleaner, and eventual replacement. While backwashing is crucial for sand and DE filters, it plays no role in the operation or cleanliness of a cartridge pool filter.
Regular care and timely replacements ensure your system maintains optimum water clarity while minimizing wear on the pump and saving water and energy. With the right maintenance habits, a cartridge filter can be a reliable, cost-effective, and environmentally friendly option for your pool filtration needs.
By understanding the unique needs of each filter type—and by recognizing the advantages of a low-maintenance, non-backwash system—you make informed choices that contribute to a cleaner, safer, and more sustainable pool environment. If you’re looking for a filter that’s easy to maintain, eco-conscious, and still provides excellent water clarity, then a cartridge pool filter may be your ideal choice.
Do cartridge pool filters need to be backwashed like sand or DE filters?
No, cartridge pool filters do not require backwashing in the same way that sand or diatomaceous earth (DE) filters do. Backwashing involves reversing the water flow to flush out trapped debris, which is essential for sand and DE filters. Cartridge filters, on the other hand, use a porous filter element to capture dirt and contaminants. Instead of backwashing, they are typically cleaned by physically removing the cartridge and rinsing it with a garden hose.
This cleaning process should be done regularly, usually every few weeks or more often depending on usage and debris levels in the pool. It’s important to let the cartridge dry completely before reinstalling it to prevent mold or mildew buildup. This simpler cleaning method is one reason why many pool owners prefer cartridge filters, although they may require more frequent cartridge replacements compared to other filter types.
What happens if I don’t clean my cartridge pool filter regularly?
Failing to clean your cartridge pool filter regularly can lead to reduced filtration efficiency and poor water circulation. As debris accumulates on the filter surface, it can restrict water flow, which places additional strain on your pool pump. This can increase energy consumption, reduce the effectiveness of your pool chemicals, and cause cloudy or unclean water.
In severe cases, a clogged filter can cause pressure buildup within the system, potentially damaging the pump or other components. Additionally, dirty filters can contribute to the growth of algae or bacteria due to stagnant water pockets within the cartridge. Regular filter cleaning is essential to maintain water clarity, pool equipment longevity, and optimal chemical balance.
How often should I clean my cartridge filter?
As a general rule, cartridge pool filters should be cleaned every 4 to 6 weeks during the peak swimming season. However, the frequency depends on several factors, including pool usage, surrounding environment (such as nearby trees or wind), and the amount of debris entering the pool. You may need to clean the filter more often during times of heavy use or after major weather events.
A good indicator that your filter needs cleaning is a rise in pressure on the filter’s pressure gauge. When the pressure exceeds the starting pressure by 8 to 10 psi, it’s time to clean the filter. Always consult your manufacturer’s recommendations and keep a regular maintenance schedule that aligns with your specific pool conditions.
How do I properly clean a cartridge filter?
To properly clean a cartridge filter, first turn off the pool pump and release pressure from the system by opening the air relief valve. Remove the filter tank lid and take out the cartridge element carefully. Use a garden hose with a spray nozzle to rinse off debris, starting from the top and working downward between the pleats. Be gentle to avoid damaging the filter media.
After rinsing, soak the cartridge in a filter cleaner solution designed to dissolve oils, minerals, and other stubborn residues. This deep cleaning should be done about once a season or more frequently in pools with high bather load. Allow the cartridge to dry completely before reinstalling it in the filter housing. Reassemble the filter housing securely and ensure all seals are intact.
When should I replace a cartridge filter instead of cleaning it?
Even with proper maintenance, cartridge filters should be replaced every 1 to 3 years depending on usage and condition. Over time, the filter media can wear out, become torn in the pleats, or develop permanent clogs that can’t be removed with standard cleaning techniques. If you notice persistent high pressure, leaking, or inability to effectively filter water despite regular cleaning, the cartridge may need replacing.
Signs such as cracks in the cartridges’ end caps, frayed or warped pleats, or diminished pool water clarity after cleaning can also indicate the filter has reached the end of its lifespan. When replacing, make sure to choose the correct replacement cartridge recommended by the manufacturer to ensure compatibility and optimal filtration performance.
What are the advantages of cartridge filters compared to sand or DE filters?
Cartridge filters offer several benefits that appeal to many pool owners. One major advantage is their ability to capture smaller particles than sand filters, typically at a filtration level of about 10 to 20 microns, which helps maintain clearer water. Additionally, they do not require backwashing, which conserves water and can reduce chemical loss associated with flushing water out during the cleaning process.
Another benefit is the ease of maintenance—most cartridge filters can be cleaned with just a hose and filter cleaner solution. They typically have fewer moving parts than DE or sand filters, leading to less mechanical complexity and potentially fewer repairs. However, they do require periodic replacement of the cartridge element and more hands-on cleaning, which should be factored into your overall maintenance routine.
Can I backwash a cartridge filter occasionally to help clean it?
While backwashing is not a standard procedure for cartridge filters, some models are designed to operate within systems that offer a backwash option. However, forcing a backwash on a system not designed for it can cause damage. Cartridge filters are intended to be cleaned manually, and using a backwash feature that isn’t intended for this type of filter may disrupt the internal components or compromise the integrity of the filter media.
If your system includes a multiport valve that offers backwash, rinse, or backwash settings, always check the manufacturer’s guidelines before performing any operation. In most cases, it’s best to stick to the manufacturer-recommended cleaning process. For most cartridge filters, this means removal and rinsing, not backwashing, is the preferred method to maintain clean and healthy pool water.