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When it comes to filtering your pool water, there are three options currently available — Diatomaceous Earth (DE), cartridge and sand. While having a choice is always nice, deciding between these three pool filter options can be difficult for any pool owner, whether they’re just building a pool, remodeling an existing one or replacing equipment.

In this post you’ll find all of the information you need to know so that you will be able to choose the right pool filter for your budget, your pool and your lifestyle.

Quick Basics About Pool Filters

All three types of filters use a screening process to remove dirt from your pool water. They are all rated (or sized) in two ways:

• Filter rate
• Filter area

The filter rate is measured in how many gallons of water can be filtered per minute (GPM) and per square foot of the area being filtered. The filter area is the total surface area of the filter area and is measured in square feet.

Pool filters are measured in the number of contaminants they are able to remove from the water. These are measured in “microns” (short for micrometer or one millionth of a meter). The lower the number of microns which can be removed by the filter, the more efficient it is.

Diatomaceous Earth (DE) Filters

Here are a few important details about Diatomaceous Earth filters:

• Can filter particles 2 microns or larger (best on the market)
• Keeps water the cleanest
• Requires more maintenance
• Not permitted in all communities
• Most expensive filter option

DE filters are literally made up of ground-up dinosaur bones. This filter is the most efficient and the most effective on the market as the DE powder is able to coat and then trap the dirt while water flows through the powder.

As effective as they are, there are downsides to owning this type of filter. Apart from not always being permitted in municipalities due to waste, they require the most maintenance (backwashing). Some states also require a separation tank if you choose to use a DE filter, as this keeps DE powder from entering public streams and sewers. The tank will also need to be taken apart one to two times a year for cleaning.

Cartridge Filters

Here are a few important details about cartridge filters:

• Can filter particles 10 microns or larger
• Zero waste
• Operates at a lower pressure than DE filters
• Doesn’t require a multiport valve (no additional plumbing) which saves money and water
• Considered the most environmentally friendly

Cartridge filters use pleated polyester to filter unwanted dirt and debris from your pool water. It’s arguably the easiest to maintain since it doesn’t require constant backwashing to remove pool chemicals. When it does require maintenance, it can be easily rinsed with your garden hose.

The downside to this type of filter is its lifespan. Unlike the other two filter options, which can last five years or more, cartridge filters will need to be replaced after two to three years of use.

Sand Filters

Here are a few important details about sand filters:

• Least expensive option
• Most popular filter type
• Oldest type of pool filter
• Least efficient (can filter up to 30 microns)
• Rarely needs backwashing

Inside each sand filter is a layer of #20 US grade silica sand (though some may contain ZeoSand or Filterglass which will increase its efficiency). As water enters the top of the filter, it is evenly distributed across the sand bed’s surface and pushed to the bottom of your filter. The fine grains of sand then trap and hold the dirt particles found in your pool water.

Sand filters will initially filter to a smaller particle size. But as the filter becomes dirtier and the flow of water decreases, the pressure rate will increase. For the filter to effectively do its job, it should be backwashed or cleaned when a pressure rate of seven or eight psi is reached.

A sand filter won’t leave your pool water as clean and clear as a DE filter or cartridge filter. But what makes it a popular choice for pool owners is its affordability and lack of maintenance. Apart from backwashing the filter, the sand will only need to be changed about once every seven years.

Don’t Pick a Filter Without Looking At Your Pump

Your pool filter and pump need to work in harmony in order to keep your pool water clean and healthy. As we touched on earlier, each filter has a gallons per minute (GPM) rating per square foot. For optimal pool operation, the filter flow rate must be equal to or greater than the GPM of your pool pump. As a general rule of thumb, your filter should have a minimum of 1 square foot for every 10,000 gallons of your pool’s capacity.

Pick the Right Pool Filter with a Trusted Pool Professional

Still in doubt about which filter is best for your pool? Contact a reputable, local pool service company for expert advice and guidance from an experienced pool professional.