Cartridge Filter Systems for Pools & Spas
By Debra Maurer
If you’re looking for a low-maintenance and inexpensive filter system for your pool or spa, a cartridge system may be the way to go. But you may be wondering, how exactly does it work and what type of maintenance is involved?
First of all, a filter cartridge includes pleated “media” or polyester filtration material that is shaped like a cylinder. The media traps debris, lotions, body oils, and other unwanted material as water flows over it. Cartridges can run at a relatively low pressure, which put less pressure on your pump, allowing the water to turnover more often; therefore, your pool water is filtered at a highly efficient level.
Cartridges come in many different sizes because they must be sized appropriately to fit the system on your pool or spa. Because of the variations in size, replacement cartridges can cost as little as a few dollars or up to $100.
One benefit to using a cartridge system is that there is no need to backwash. Required on D.E. and sand filtration systems, backwashing is the process of running your pool water in reverse for approximately two minutes (until the water runs clear) in order to clean the filter. Sand and D.E. filters must be backwashed whenever the pressure gauge is 8 – 10 psi (pounds per square inch) above the start-up pressure. The frequency will depend on the bather load in your pool, filter size, and flow rate. This may be as often as once a week or as little as once every two to three months. Maintaining proper water balance will reduce how often D.E. and sand filtration systems needed to be backwashed.
While a cartridge system saves a tremendous amount of water, some maintenance is required to clean and replace the cartridges.
Replacing a Filter Cartridge
How often you’ll need to a replace your filter cartridge depends on the frequency of pool/spa use and how well you maintain the chemical balance. John Antretter, CEO of Pleatco, LLC, manufacturer of filter cartridges says, “For regions with a four-month pool season, the cartridge should generally be replaced once a year. In a heavily used pool, or one used year-round, you’ll probably have to replace it more often.”
In a spa, you need to replace your old cartridge with a brand new one every three months. “In the hot water environment of a spa and having a much higher bather load than a pool,” says Antretter. “A spa filter cartridge should be changed after about three months, the cartridge may still look clean, but particles from lotions, sweat, and other contaminants will have built up in the media or filtration fabric. At that point, it’s time to replace it.”
Cleaning a Filter Cartridge
An increase in your pool pump’s pressure gauge—about 8 psi above normal pressure—indicates when the cartridge is fully loaded and requires cleaning. For hot tubs and spas, a more specific routine should be established based on how often the spa is used.
Most experts recommend alternating between two cartridges so you have a clean one to insert right away while the other one is being cleaned. It is also imperative that you follow the manufacturer’s cleaning instruction so the media remains in tact, but here are a few guidelines:
Use a garden hose with a straight flow and work from the top down, holding the nozzle at a 45-degree angle. Be sure to get in between the pleats. This should remove most dirt and debris. To remove smaller particles, allow the cartridge to dry. Then carefully brush the filter media with a soft brush or use a line of compressed air to remove the particles. If a film of algae or oil develops on the media, you should remove it as soon as possible by soaking in a filter element cleaner for at least an hour or sometimes, overnight. Again, you should follow the manufacturer’s specific instructions, especially regarding which cleaning solution to use.
Photo courtesy of Pleatco, Inc.