Keeping your swimming pool clean and safe largely depends on the performance of your filtration system. Over time, pool filters accumulate dirt, oils, debris, and minerals that hinder their efficiency. One effective method of maintaining your filters is soaking them in a cleaning solution. But what should you actually soak your pool filters in to clean them?
In this in-depth guide, we explore different cleaning solutions suitable for various types of pool filters—cartridge, sand, and diatomaceous earth (DE)—and help you understand how to properly maintain these critical components of your pool system.
Why Cleaning Your Pool Filters Matters
Pool filters are the unsung heroes of a clean and healthy pool. Whether you have a cartridge filter, sand filter, or DE filter, each plays a vital role in keeping your pool water clear by trapping particles and contaminants. However, when filters become dirty or clogged, they can no longer perform effectively, leading to:
- Cloudy or murky water
- Increased chemical demand
- Higher energy bills due to stressed pump operation
- Shortened lifespan of your filtration system
This is why regular filter maintenance—especially deep cleaning through soaking—is essential.
Types of Pool Filters and Their Cleaning Needs
Pool filters come in three main types, each with distinct cleaning requirements. Understanding your filter type will guide the best soaking method to use.
1. Cartridge Filters
Cartridge filters use a pleated paper or polyester element to remove debris from the water. They require more frequent cleaning than other filters, especially in pools with heavy usage or in high-debris areas.
2. Sand Filters
Sand filters rely on sand media to filter out contaminants. They generally only need backwashing instead of frequent removal. However, they still benefit from occasional deep cleaning via soaking.
3. DE Filters
Diatomaceous earth filters use a fine powder (DE) that coats grids or plates to trap tiny particles. These filters are highly efficient but require specialized cleaning methods to ensure optimal performance.
Best Cleaning Soaks for Pool Filters
Knowing what to soak your pool filters in can make a big difference in your pool maintenance routine. Let’s take a look at the best options for each filter type.
1. Water and Filter Cleaner (Universal Use)
Using a commercial filter cleaner mixed with water is often the best bet for a thorough cleaning. These are specially formulated to break down oils, metals, and contaminants that regular rinsing can’t remove.
Steps for Using a Filter Cleaner:
- Remove the filter elements (cartridge, DE grids, etc.)
- Rinse them off with a garden hose to remove loose debris
- Prepare a soaking solution as per the product’s instructions
- Soak for the recommended time (usually 6–12 hours)
- Rinse thoroughly before reinstalling
Popular options include products such as Pleatco Filter Cleaner, Natural Chemistry Filter Soak, and Parker & Sons Filter Cleaner.
2. Muriatic Acid Solution (Primarily for DE and Sand Filters)
For filters with heavy calcium or mineral buildup, muriatic acid (hydrochloric acid) can be a powerful solution—but it must be used carefully.
Steps for Muriatic Acid Use:
- Always add acid to water, never water to acid
- Mix 1 part muriatic acid to 20 parts water for light buildup, or 1:10 for heavy scaling
- Soak the grids or sand for 10–15 minutes
- Wear gloves, goggles, and ensure proper ventilation
- Discard the solution in a safe, legal manner and rinse components thoroughly
Note: This method is not recommended for cartridge filters due to the acidic nature of the solution. Always use acid cleaning sparingly to prevent damage to filter material.
3. TSP (Trisodium Phosphate)**
TSP is a common cleaning agent effective at breaking down oils and dirt in filters. It’s typically used for cartridge filters.
How to Clean with TSP:
- Dissolve one cup of TSP in 5 gallons of warm water
- Soak the filter cartridge overnight
- Rinse thoroughly before reinstalling
CAUTION: Handle TSP with care and avoid inhaling fumes. It’s also recommended to rinse the solution down the drain far from plants or waterways.
4. Vinegar and Water Solution
For homeowners seeking a natural pool filter cleaning method, vinegar is a safe, affordable option, especially for light cleaning or removing small amounts of calcium.
Steps for Soaking in Vinegar:
- Mix equal parts white vinegar and water in a large container
- Completely submerge the filter element
- Allow it to soak for 2–3 hours
- Rinse well before returning to the filter housing
While not strong enough for heavy buildup, vinegar can serve as a routine maintenance soak between deeper cleanings.
5. Borax and Water Mix
Borax—a natural mineral compound with mild alkaline properties—can help loosen organic dirt and algae buildup in your filters.
Recommended Use:
- Dissolve 1 cup of borax in 5 gallons of warm water
- Soak your pool filter for 6–8 hours
- Flush thoroughly to remove any remaining particles
This method is most effective for cartridge filters and DE filters but should not be used for sand filters.
How Often Should I Clean and Soak My Pool Filters?
Maintaining cleaning intervals is as crucial as choosing the right cleaning solution. Here’s a general cleaning frequency based on filter type:
| Filter Type | Rinse Frequency | Soak Frequency |
|---|---|---|
| Cartridge | Every 1–2 weeks | Every 3–6 months / as needed |
| Sand | Backwash weekly | 1–2 times per year or as buildup occurs |
| DE | Backwash weekly | Every 3–4 months / after heavy use |
Remember: actual frequency may vary depending on bather load, water chemistry, and environmental factors like pollen, dust, or leaves.
How to Soak Your Pool Filters the Right Way
Soaking your filter incorrectly can lead to damage or improper cleaning. Follow these best practices for optimal results:
1. Safety First: Protective Gear and Ventilation
When handling any chemicals—especially muriatic acid or TSP—ensure you wear appropriate safety gear such as gloves, eye protection, and a mask. Work in a well-ventilated area and keep children and pets away.
2. Choose the Right Container
The soaking container should be large enough to fully submerge the filter element without distortion. Use non-metallic containers (plastic buckets or tubs) to avoid chemical reactions and corrosion.
3. Don’t Reuse Soaking Solutions
Once the solution has been used for soaking, particularly acid-based solutions, discard it properly. Reusing them can reintroduce contaminants to your filter or damage the system.
4. Timing is Important
Over-soaking can harm filters, especially cartridge types. Don’t leave your filters soaking for longer than recommended by the product label or your filter’s manufacturer.
5. Final Rinse is Crucial
After soaking, a thorough rinse with clean water is essential to remove chemical residue, oils, or loosened particles. Failure to rinse properly can introduce contaminants back into your pool water.
Best Practices for Prolonging Filter Life After Soaking
Maintaining a clean filter isn’t just about how you soak it. It’s also about how you reinstall and maintain it over time.
Reinstall with Care
Handle cartridge or DE grids gently to prevent tearing or damaging the fabric. Also, ensure all gaskets, o-rings, and seals are properly in place.
Monitor Pressure Gauges
For sand and DE filters, monitor pressure gauges closely. A rise of 8–10 psi above your starting clean pressure is a sign it’s time to clean or backwash.
Balance Your Pool Water
Properly balanced water chemistry plays a big role in how often filters get dirty. Ensure pH, alkalinity, hardness, and sanitizer levels are within recommended ranges to prevent scale buildup and early clogging.
Use a Pre-Filter for Pools with Heavy Debris
Pools surrounded by trees or open fields will benefit from using a pre-filter sock or mesh bag on pool skimmers. This traps large debris before it clogs your filters, improving efficiency.
Environmental and Disposal Considerations
Proper disposal of soaking solution is just as important as the cleaning itself. Here’s what to bear in mind:
- Never pour chemical solutions into storm drains or lawns
- Check local regulations for proper chemical disposal guidelines
- Neutralize muriatic acid with baking soda before disposal
Signs Your Pool Filters Need Cleaning
You don’t always have to set a cleaning schedule to know when to clean your filters. Here are common signs that your filters might need attention:
- Low water flow or high filter pressure
- Cloudy pool water despite proper chemical levels
- Longer filter cycles with less clarity
- Visible dirt accumulation on filter elements
Conclusion: Choose the Right Strategy for Your Filter
To answer the question, “What should I soak my pool filters in to clean them?”, the best solution depends on your filter type and the level of buildup you’re dealing with.
Cartridge filters do well with filter-specific cleaners or TSP soaks, while DE and sand filters respond best to muriatic acid cleaning for heavy mineral scaling. Vinegar and borax offer gentler, natural alternatives for mild cleaning.
Regular filter maintenance will not only extend the life of your filtration system but also improve water clarity, reduce chemical usage, and save on energy. Keep a consistent routine, and don’t hesitate to tackle deep cleanings when the signs call for them.
By properly maintaining your pool filters, you ensure your swimming pool remains a clean, safe, and enjoyable part of your home all season long.
What are the most common solutions for soaking pool filters?
Soaking pool filters is a crucial part of regular pool maintenance to ensure optimal filtration and water clarity. The most commonly used solutions include a mixture of water and trisodium phosphate (TSP), pool filter cleaner products, diluted chlorine bleach, and vinegar solutions. Each method has its own advantages, depending on the type of filter you have and the level of buildup or contamination. TSP is effective for removing oils and grease, while vinegar is a mild, eco-friendly option that works well on calcium deposits.
For best results, it’s important to follow the manufacturer’s recommendations for filter cleaning and choose a cleaning solution compatible with your filter type—whether it’s cartridge, sand, or diatomaceous earth (DE). Always use gloves and eye protection when handling cleaning chemicals, and thoroughly rinse the filter after soaking to avoid introducing harmful substances back into the pool. Cartridge filters, for example, respond well to deep cleaning with TSP or commercial filter cleaners, while DE filters might need special attention to avoid damaging the grids.
Can I use vinegar to soak my pool filter?
Yes, vinegar is an effective and natural solution for soaking pool filters, especially when dealing with mineral buildup or mild contamination. A solution of equal parts water and white vinegar can help dissolve calcium deposits and other scale without the need for harsh chemicals. This method is particularly useful for cartridge filters that have accumulated mineral residue over time. Soaking overnight or for several hours often yields good results.
However, vinegar is not a powerful degreaser or disinfectant, so it may not be sufficient for heavily soiled or oily filters. In such cases, combining vinegar with a light brushing or using a more aggressive cleaning method like a commercial filter cleaner may be necessary. Always rinse the filter thoroughly after soaking it in vinegar to remove any residual acidity before reinstalling it in the filtration system.
How do I properly soak a cartridge filter?
To properly soak a cartridge filter, start by rinsing it with a garden hose to remove loose debris. Then prepare a cleaning solution—either a commercial filter cleaner, a diluted bleach solution (1 part bleach to 10 parts water), or a TSP mixture (1–2 cups per 5 gallons of water). Submerge the filter in the solution and let it soak for several hours or overnight, depending on the level of buildup and the cleaner’s instructions.
After soaking, gently scrub the filter with a soft brush to dislodge any remaining dirt or residue, then rinse it thoroughly with clean water. Make sure no cleaning agents are left on the filter before reinstalling it in the system to avoid contamination of pool water. Avoid using high-pressure water or harsh abrasives during cleaning, as they can damage the pleats or reduce the efficiency of the filtration medium.
Is bleach a safe option for soaking pool filters?
Bleach can be safely used to soak certain types of pool filters, particularly cartridge filters that are heavily contaminated with organic matter or algae. A diluted solution of bleach and water (typically 1 part bleach to 10 parts water) effectively sanitizes and removes biological buildup without damaging the filter media. It’s important to use household bleach without added fragrances or thickeners for this purpose.
However, bleach should be used with caution, and the filter must be rinsed thoroughly afterward to ensure no chemical residue remains. Bleach is not recommended for DE or sand filters as it may damage the internal components or grids. Always work in a well-ventilated area and wear protective gloves and eyewear when handling bleach. If you’re unsure whether your filter is compatible, consult the manufacturer’s guidelines before proceeding.
How often should I soak and clean my pool filter?
The frequency with which you should soak and clean your pool filter depends on pool usage, water chemistry, and environmental factors. As a general rule, cartridge filters should be soaked every 6 months or sooner if you notice a drop in filter pressure or reduced water clarity. Pools in areas with high pollen, debris, or heavy swimmer traffic may require more frequent cleanings.
For DE and sand filters, deep cleaning every 6–12 months is often sufficient, though routine backwashing or media replacement plays a significant role in their maintenance. Always monitor your filter’s pressure gauge—when it rises 8–10 psi above the starting pressure, it’s likely time to clean your filter. Incorporating regular filter maintenance into your pool care schedule helps extend the life of the equipment and ensures the water stays clean and safe for swimming.
What should I avoid when soaking my pool filter?
When soaking your pool filter, there are several things to avoid to prevent damage or inefficiency. Never use undiluted bleach, strong acids, or caustic chemicals unless specifically recommended by the filter’s manufacturer. Also, avoid using a pressure washer to clean the filter unless the manufacturer approves it, as high-pressure water can damage the pleats or internal structure.
Another common mistake is allowing the filter to dry out during the soaking process or leaving it submerged for too long in a chemical solution, which can degrade the materials over time. Additionally, don’t skip the rinsing stage after soaking—residual cleaning agents can enter the pool water and affect chemistry, irritate swimmers, or harm the equipment. Always follow the cleaner’s instructions and manufacturer guidelines for safe and effective filter cleaning.
Are there commercial filter cleaners that work better than homemade solutions?
Yes, commercial filter cleaners can be more effective than homemade solutions, especially when dealing with heavily soiled or oil-laden filters. These products are specially formulated to break down oils, lotions, metals, and organic contaminants that commonly accumulate in pool water. Unlike general-purpose cleaners like TSP or vinegar, commercial products often contain surfactants and chelating agents designed to target specific types of residue and work more efficiently.
They also offer convenience and consistency—each bottle provides clear instructions, safe handling guidelines, and is typically tested for compatibility with various pool filter types. Some popular brands include Zodiac, Poolmaster, and ProTeam Filter Cleaner. While homemade solutions may work for light cleaning, commercial cleaners are recommended for deeper maintenance or when preparing to winterize your pool. However, always rinse the filter thoroughly after using any commercial cleaner to ensure no residue is left behind.