What can I soak my pool filter in to clean it?

Quick Answer

The most common and effective solutions for soaking pool filters to clean them are muriatic acid, filter cleaner, or trisodium phosphate (TSP). Muriatic acid helps dissolve mineral deposits, oil and scale buildup. Filter cleaner is a formulated solution to break down organic contaminants and oils. Trisodium phosphate (TSP) is a heavy-duty cleaner that removes oils, scale and residues.

What Causes Pool Filter Dirt Buildup

Over time, pool filters can accumulate dirt, oils, scale, calcium, algae and other debris that clogs the filter media and reduces water flow. This dirt buildup occurs due to:

• Oils, sweat and personal care products that transfer into the water from swimmers’ skin and hair.
• Calcium and mineral deposits from the water itself.
• Debris such as leaves, dust and pollen that gets into the pool.
• Algae, bacteria and other microorganisms that grow in the filter.

These contaminants stick to the filter media (sand, DE, cartridges) and restrict water flow. Soaking the filter periodically helps dissolve and flush away these built-up deposits for cleaner filter media.

Choosing the Right Soak Cleaner

The best soak cleaner depends on the specific contaminants in your filter. Common options include:

Muriatic Acid

Also called hydrochloric acid, muriatic acid effectively dissolves inorganic mineral buildup like calcium, limescale and metallic stains. It also removes rust deposits. It is highly acidic, so safety precautions are needed, but it is inexpensive and fast-acting. Use for mineral scale buildup.

Pool Filter Cleaner

This is a formulated chemical solution designed specifically for breaking down organic oils, suntan lotions, cosmetics and similar residues that stick to the filter. Look for formula with detergents and enzymes to dissolve organics. Use for buildup of body oils and sunscreens.

Trisodium Phosphate (TSP)

TSP is a heavy-duty cleaner that removes oils, grease, calcium, algae, scale and other common pool filter gunk. It is very alkaline which helps dissolve minerals and neutralize acids. Its cleansing action breaks down all types of residue. Use TSP for severe, mixed contaminant buildup.

Dishwasher Detergent

Ordinary dishwasher detergent contains surfactants and enzymes that can help break down organic oils and grime. Make sure it does NOT contain bleach. Though not as powerful as formulated cleaners, it offers a more natural, inexpensive option suitable for maintenance cleaning.

Citric Acid

Derived from citrus fruits, citric acid works well for removing calcium carbonate scale buildup through chelation. It also helps break down minerals, rust and alkaline deposits from pool water. Though not as immediately potent as muriatic acid, citric acid is all natural.

How to Soak Pool Filters

Soaking should be done periodically to maintain clean filters. Follow these steps:

1. Remove the filter from the pool system following the manufacturer’s instructions. Cartridge types unscrew while DE and sand filters have a release valve. Take it outside to an open area.
2. Spray off loose debris with a garden hose if needed.
3. Plug the openings so soak solution does not leak out – use rubber plugs or tape.
4. Prepare soak solution. Mix according to product label, usually a ratio of 2-4 cups cleaner to 1 gallon of water. Use a large bucket or plastic tub.
5. Submerge the filter in the solution, weighting it down if needed to keep it fully soaked.
6. Let soak for 6-12 hours for heavy soiling or 1-2 hours for maintenance cleansing.
7. Remove filter and rinse very thoroughly with fresh water to flush out all residue.
8. Reinstall filter in the pool system according to manufacturer’s directions.
9. Backwash the system and test water balance before allowing swimming again.

Safety Tips

– Use caution when handling muriatic acid or other acidic cleaners – wear gloves, eye protection and have proper ventilation.
– Rinse tissues thoroughly to avoid chemical residue contact with pool water.
– Never soak filters in bleach – this will damage materials.
– Dispose of used cleaning solution properly.
– Follow all product label precautions.

Alternative Cleaning Methods

While soaking is very effective, it is not the only way to clean pool filters. Other options include:

Backwashing

Backwashing the filter sends water through it in reverse to flush out accumulated gunk. This works for minor cleaning and maintenance. Soaking is still needed periodically for heavier buildup.

Spray Cleaning

Special spray-on filter cleaners foam up and break down oils and residues. This is quicker than soaking but mainly just surface cleans. Harsher soak-in cleaners work better for deep buildup.

Automatic Cleaners

Some robotic pool cleaners will attach to the filter and scrub it clean. This automates the process but mainly just removes surface dirt, not dissolved scale or oils. Check if your current cleaner has this function or consider new models with this feature.

Replace Cartridges

For cartridge filters with permanent buildup, simply replace the cartridge. Reusable media types can be washed repeatedly. Have spare cartridges available for quick swaps.

Professional Service

Many pool service companies offer professional cleaning services for severely fouled filters. This thoroughly restores filters but is more costly than DIY methods. Consider for older filters in need of heavy-duty rejuvenation.

Conclusion

To clean pool filters, periodically soaking them in muriatic acid, filter cleaner or TSP effectively removes built-up gunk like oil, scale and residues. This restores water flow and filtration performance. Use the appropriate formula for your filter’s particular contaminant issue and allow to soak fully before rinsing clean. With regular cleaning soaks, you can keep your pool filter working in tip-top shape all season long.