The Ultimate Guide to Swimming Pool Cartridge Filters: Everything You Need to Know

Swimming pools are a wonderful addition to any home, providing a fun and refreshing way to relax. However, keeping pool water clean and safe requires proper filtration. One of the most popular filtration systems today is the cartridge filter. Whether you're a seasoned pool owner or new to pool maintenance, this guide will give you a comprehensive understanding of swimming pool cartridge filters, including how they work, their benefits and why they are a superior option for many pool owners.

What Are Cartridge Filters?

Cartridge filters are one of the three main types of pool filtration systems, alongside sand filters and diatomaceous earth (DE) filters. These filters use a cylindrical element made of pleated polyester or other synthetic material to trap dirt, debris and contaminants from the water. The cartridge is housed inside a filter tank, and as water flows through the cartridge, particles are trapped, allowing clean water to be returned to the pool.

How Do Cartridge Filters Work?

The functioning of a cartridge filter is relatively simple yet highly effective. 

Here’s how the process works:

1. Water Entry: Pool water enters the filtration tank, typically through a pump that circulates the water.

2. Filtration: The water passes through the pleated cartridge filter. As it flows through the filter media, dirt, debris, oils and other particles are caught in the pleats. The pleats increase the surface area, allowing the filter to trap more contaminants.

3. Clean Water Return: The clean, filtered water exits the tank and returns to the pool, ensuring crystal-clear water for swimming.

Cartridge filters don’t use sand or DE powder, making them low-maintenance and environmentally friendly. This simplicity is a key reason why many pool owners prefer them over other filtration systems.

Why Are Cartridge Filters Important?

Cartridge filters play a critical role in maintaining the water quality in your swimming pool.

 Here's why they are indispensable:

• Removes Contaminants: Pools are exposed to various impurities, including leaves, insects, body oils, sunscreen residues and other pollutants. Cartridge filters efficiently capture these particles, ensuring the water stays clean.

• Prevents Cloudy Water: Proper filtration is essential to avoid cloudy or murky water, which can result from poor water circulation and filtration. Clean water is not only more inviting but also safer for swimmers.

• Reduces Algae Growth: By consistently filtering out debris, cartridge filters help reduce the nutrients algae feed on, lowering the risk of an algae bloom in your pool.

• Enhances Chemical Efficiency: Clean water allows your pool chemicals, such as chlorine or bromine, to work more effectively. If the water is filled with debris, the chemicals will be consumed more quickly, requiring you to add more.

The Benefits of Cartridge Filters

Compared to other types of pool filters, cartridge filters offer a range of benefits that make them an excellent choice for residential pools:

1. Superior Filtration

Cartridge filters can filter out particles as small as 10-15 microns (a human hair is about 70 microns thick). This is finer than sand filters, which typically filter particles down to 20-40 microns. The ability to filter out smaller particles means cleaner, clearer water.

2. Energy Efficiency

Since cartridge filters have a larger surface area, they allow for more water flow with less pressure. This reduces the workload on your pool pump, saving energy and lowering your utility bills.

3. Easy Maintenance

Maintaining a cartridge filter is much easier compared to sand and DE filters. Cartridge filters don’t require backwashing, which is a water-wasting process used in other filter types. Instead, the cartridge needs to be removed, cleaned and reinserted when dirty.

• Cleaning Frequency: The cleaning process is simple—just remove the cartridge, rinse it with a garden hose and it’s ready to use again. Depending on usage, cartridges may need to be cleaned every 2-6 weeks.

• Replacement: Cartridge filters generally need to be replaced every 1-2 years, though the frequency can vary based on usage and maintenance practices.

4. Environmentally Friendly

Unlike sand filters, cartridge filters don’t require backwashing, which can waste hundreds of gallons of water each time. Instead, they can be cleaned and reused multiple times, reducing water waste and chemical loss.

5. Compact Size

Cartridge filters are often more compact than sand or DE filters, making them an ideal option for pool owners with limited space. They can fit in tighter areas without sacrificing filtration quality.

How to Choose the Right Cartridge Filter

When selecting a cartridge filter for your pool, there are a few key factors to consider:

1. Pool Size

Larger pools require more robust filtration systems to keep the water clean. Ensure the cartridge filter you select is rated for the volume of water in your pool. Pool cartridge filters are rated based on gallons per minute (GPM) and pool size, so choose one that can handle your pool’s capacity.

2. Flow Rate

Check the flow rate of your pool pump and make sure the cartridge filter can handle the water flow. The pump’s GPM should not exceed the filter’s capacity to avoid damaging the cartridge.

3. Filtration Surface Area

The surface area of the filter cartridge, which is determined by the pleats, affects how well the filter can capture debris. The more pleats, the more surface area the filter has, which can help it last longer and require less frequent cleaning.

4. Brand and Quality

Choosing a high-quality brand with a reliable reputation ensures you get a durable and efficient filter. Opt for trusted pool equipment brands that provide a good warranty and support.

How to Maintain Your Cartridge Filter

Proper maintenance is crucial to prolonging the life of your cartridge filter and ensuring your pool stays clean. 

Here are a few tips to keep your filter in peak condition:

• Regular Cleaning: Depending on usage, clean the cartridge every few weeks. A quick rinse with a garden hose should suffice, but for more thorough cleaning, you can soak the cartridge in a filter cleaner solution to remove oils and grime.

• Deep Cleaning: At least once a season, remove the cartridge and perform a deep clean by soaking it overnight in a solution of water and pool filter cleaner.

• Monitor Pressure: Most filter tanks have a pressure gauge. A spike in pressure (usually 8-10 PSI above normal) is a sign that the cartridge needs cleaning. Monitoring the pressure helps you avoid overworking the pump.

• Replacement: When you notice wear and tear, such as broken pleats, or if the filter is no longer cleaning effectively, it’s time to replace the cartridge. Don’t wait too long to replace the filter, as a worn-out filter will compromise water quality.

A cartridge filter is one of the most efficient and convenient options for keeping your swimming pool clean and safe. Its ability to filter out fine particles, energy efficiency and ease of maintenance make it an excellent choice for most pool owners. By understanding how cartridge filters work and the benefits they offer, you’ll be well-equipped to maintain crystal-clear water all season long.

If you’re looking to install a new pool filtration system or upgrade your current one, consider investing in a cartridge filter to enjoy clear, sparkling pool water with less hassle.