A cartridge filter is an advanced filtration system that utilizes a highly efficient, replaceable pleated cartridge to trap microscopic debris. Unlike sand filters, they require no backwashing, which saves water and minimizes your maintenance efforts. They are a sleek, eco-friendly solution for pristine water clarity.
When deciding how to keep your pool water clean, the filtration system you choose dictates exactly how much manual labor you will be doing all summer. For decades, massive sand filters dominated the industry. However, cartridge filters have become the modern standard for residential pools because they offer a perfect balance of excellent water clarity and incredibly low maintenance. Understanding how these pleated filters work will help you get the longest lifespan out of your equipment.
How Does a Cartridge Filter Work?
Instead of forcing water through a heavy bed of sand or loose powder, a cartridge filter relies on surface area.
Inside the sleek fiberglass or plastic filter tank sits one or more cylindrical cartridges. These cartridges are made of spun polyester material folded into hundreds of tight pleats. As your pool pump pushes dirty water into the tank, the water is forced completely through the pleated fabric. The fabric catches dirt, oils, and algae spores, allowing only perfectly clean water to pass through the center core and return to your pool.
Because the polyester fabric is folded so many times, a single cartridge provides a massive amount of surface area. This means the filter can trap a huge volume of dirt before the water pressure inside the tank begins to rise.
Comparing Filtration Power
Pool filtration capability is measured in microns (one millionth of a meter). The human eye can only detect particles down to about 40 microns.
Sand filters only capture debris down to 20 to 40 microns, meaning a lot of microscopic dust slips right back into your pool. Cartridge filters perform significantly better. They easily trap debris as small as 10 to 15 microns. This level of filtration removes the fine suspended particles that cause dull, hazy water.
While Diatomaceous Earth (DE) filters catch even smaller particles, they require dealing with messy, hazardous powders and constant backwashing. Use the tool below to see exactly how a cartridge filter balances performance and maintenance compared to the alternatives:
The Step-by-Step Cleaning Process
The biggest advantage of a cartridge system is that you never have to backwash it. Backwashing a sand or DE filter dumps hundreds of gallons of chemically treated, heated pool water directly into your yard. With a cartridge filter, you simply remove the element and wash it off.
You will know it is time to clean the filter when the pressure gauge on the top of the tank rises 8 to 10 PSI above its normal, clean starting pressure.
1.Turn Off the Pump and Release Pressure:Safety first.
Turn off the pool pump entirely. Then, open the air relief valve on the very top of the filter tank to release all the built up internal pressure.
2.Remove the Filter Cartridge:
Unscrew the locking ring or clamp holding the tank together. Remove the lid and carefully lift the dirty cartridge out of the tank.
3.Hose It Down:
Using a standard garden hose with a spray nozzle, spray the cartridge starting from the top and working your way down. Get deep between the pleats to wash away the accumulated dirt and debris.
4.Use a Filter Cleaner Spray:Optional for heavy oils.
If the filter is coated in sticky sunscreen or body oils, spray it with a dedicated chemical filter cleaner. Let it sit for 15 minutes before doing a final rinse.
5.Reassemble the Tank:
Place the clean cartridge back into the tank. Secure the lid and locking ring tightly. Turn the pump back on and close the air relief valve once a steady stream of water sprays out.
Extend Your Cartridge Lifespan with DualPool
A high quality filter cartridge should last between three to five years before the pleats begin to tear and require replacement. However, if your pool constantly battles heavy pollen, fine dust, or suspended metals, those microscopic particles will embed themselves deep into the polyester fabric and shorten its life.
You can drastically reduce the strain on your filter by using the DualPool 2-in-1 Pool Clarifier. By placing this advanced formula in your skimmer basket, it continuously groups together the ultra fine suspended solids and heavy metals before they reach your filter. By binding these tiny particles into larger clumps, DualPool prevents the fine dust from cementing into the microscopic pores of your cartridge. This keeps the water flowing freely, lowers your tank pressure, and extends the life of your expensive filter elements.
Frequently Asked Questions (FAQ)
Can I pressure wash my pool filter cartridge?
No. You should never use a high pressure power washer on a pleated pool filter. The extreme force of a pressure washer will instantly shred the spun polyester fabric and permanently destroy the filter’s ability to catch dirt. Always use a standard garden hose with a regular spray nozzle.
How often do I need to clean my pool cartridge filter?
It depends on the size of your filter and how often you use the pool. Most properly sized residential cartridge filters only need to be cleaned every three to six months. However, if you recently suffered a severe algae bloom, you will likely need to clean the filter immediately after clearing the green water.
Can I clean my filter cartridge with muriatic acid?
You should only use a diluted muriatic acid bath if your filter is heavily scaled with hard calcium deposits. If you soak a filter in acid without first removing the oily buildup using a degreaser, the acid will permanently bake the oils directly into the fabric, completely ruining the filter.