How to Select The Best Pool Filter

Pool filters are as important to your pool as your kidneys are to your own body. We know that sounds kind of gross, but it’s true. Though chlorine and other sanitizers work to kill bacteria and other contaminants, the filter is what actually removes them from the water. Without it, your pool water would grow cloudy and fill with debris. Not exactly fun for swimming.

So how do you choose the best one? It’s not about which one is the least expensive, though cost is certainly a factor. You want a filter that will trap contaminants, be easy to clean and maintain, and last more than just a few seasons. In order to make the best selection for your pool, first get a handle on your options.

Pool Filter Types

The first step to choosing the best filter is knowing what your options are. You have three types of filters to choose from: sand, cartridge, and diatomaceous earth, or D.E. Price, replacement frequency, and filtration rates differ by type.

But before you can accurately compare pool filter types and how well they work, you need to know about microns.

What the Heck is a Micron?

Pool filters measure the size of contaminants they’re capable of removing in microns. It’s short for micrometer, which is one millionth of a meter.

Having trouble picturing just how small that is? A single strand of human hair is about 50 microns, or about .05 millimeters in diameter. Some bacteria measures about 2 microns, or about .002 millimeters in diameter.

How small is a micron?

Whether they’ve been killed by chlorine or not, bacteria and other contaminants can only be filtered out if the filter media—the material that actually does the filtering—is fine enough to collect those teeny, tiny particles.

Sand Filters

If you’re on a budget, and you want to spend minimal time on maintenance, a sand filter is the best choice for you. It’s also optimal for large pools because it won’t clog as easily as other filters.

Your pool pump sucks water in from the skimmers, then pushes it through a large filtration tank full of sand. The standard media used inside the tank is #20 silica sand. It grabs particles that measure 20 microns and larger If you click this link and make a purchase, we earn a commission at no additional cost to you. .

Each grain of sand is, for lack of a better word, prickly. If you could look at it under a microscope, you’d see it has lots of little rough edges all around it, which is how it grabs contaminants and debris that pass through the filter.

As weeks and years pass, and more water flows through the filter, those rough edges are slowly worn down by erosion, eventually becoming smooth surfaces that aren’t able to capture anything.

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At the same time, the particles trapped within the sand will build up over the life of the filter. This can actually help trap smaller particles, even as the sand itself begins to smooth out. But eventually, it will prevent proper water flow through the filter, reducing the filter’s efficiency.

A pressure gauge on the side of the filter will alert you to increasing internal pressure—a sign it’s time to backwash the filter. This easy cleaning method the filter reverses the water flow, flushing all the debris to waste.

Because the silica captures particles of 20 microns or larger, you’ll really need to stay on top of your pool water chemistry. If there’s not enough sanitizer in your pool to kill those tiny, 2-micron bacteria, a sand filter isn’t going to catch them either, and they’ll be floating around in your pool with you.

HTH Pool Filter Sand - 50 lbs. Price:
HTH Pool Filter Sand - 50 lbs.
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Sand Alternatives

Although #20 silica is the standard media in sand filters, you can slightly increase filtration efficiency by adding D.E. powder If you click this link and make a purchase, we earn a commission at no additional cost to you. after backwashing or replacing the sand.

You can also entirely replace the silica with one of two alternatives.

Pool Filter Sand Media

ZeoSand: This is made from a mineral called zeolite. You need only half as much If you click this link and make a purchase, we earn a commission at no additional cost to you. (by weight in pounds) as standard pool filter sand. It’s crystal-like shape naturally traps smaller contaminants than silica. This improves water clarity and requires less frequent backwashing. ZeoSand lasts about five years, so its lifespan is similar to silica.

Filter Glass: This is finely crushed, recycled glass. Don’t worry about cuts—it’s smooth to the touch. It has a negative electrical charge which attracts positively charged particles, such as iron and manganese. You can use about 20% less filter glass than you would silica, while filtering debris as small as 5 microns If you click this link and make a purchase, we earn a commission at no additional cost to you. . It also lasts up to three times longer than pool sand.

Harsco Metals & Minerals Filter Glass - 40 lbs. Price: $34.94
Harsco Metals & Minerals Filter Glass - 40 lbs.
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Sand Filter Pros:

Sand Filter Cons:

ZeoSand Pool Filter Sand Alternative - 50 lbs. Price: $31.95
ZeoSand Pool Filter Sand Alternative - 50 lbs.
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Cartridge Filters

Though they’re typically a bit more expensive than sand filters, cartridge filters are just as easy to maintain, and are more effective as long as you don’t have a huge pool.

Inside a tank slightly smaller than their sand cousins is a plastic cylinder surrounded by pleated polyester filter media and capped on each end. Water flows into the tank and through the pleats. Debris as small as 10 microns If you click this link and make a purchase, we earn a commission at no additional cost to you. is captured in the filter, then clean water heads back to the pool.

Cartridges are energy efficient and inexpensive. As the filter collects contaminants, it’ll need cleaning. Rather than backwashing, you’ll simply remove the cartridge from the tank, and spray it with a hose to remove debris and dirt.

Occasionally, you’ll want to spray it down with filter cleaner If you click this link and make a purchase, we earn a commission at no additional cost to you. , and on a regular basis, soak it in diluted muriatic acid If you click this link and make a purchase, we earn a commission at no additional cost to you. or a chemical filter cleaning solution. While this is a bit more physical work for you than backwashing, it wastes less water.

HTH Pool Cleaner Filter Cleaner - 32 oz. Price: $9.84
HTH Pool Cleaner Filter Cleaner - 32 oz.
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Cartridge Filter Pros:

Cartridge Filter Cons:

Tier1 Replacement Pool Filter Cartridge - Hayward C2025 - SwimClear C2020 C2025 - Filbur FC-1235 - Pleatco PA50SV - Unicel C-7447 Price: $34.90
Tier1 Replacement Pool Filter Cartridge - Hayward C2025 - SwimClear C2020 C2025 - Filbur FC-1235 - Pleatco PA50SV - Unicel C-7447
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Diatomaceous Earth (D.E.) Filters

The most expensive, maintenance-intensive option also happens to filter the smallest particles If you click this link and make a purchase, we earn a commission at no additional cost to you. of all three types of filters: 5 microns.

D.E. filter tanks contain grids or “fingers” covered in the crumbly, white powder. The powder is made from the crushed fossilized remains of tiny, aquatic organisms called diatoms. Though D.E. and sand pool filters are different, the fossils in D.E. are also composed of silica. The powdery substance can be found in pest control, cosmetics, and even toothpastes, but D.E. made for pool filters is heat-treated to work as a filtration media. So don’t go sprinkling that pest-control powder into your pool filter when you run out of D.E., mm-kay? We’re talking about different kinds of pests here.

Diatomaceous Earth Powder - 25 lbs. Price: $26.69
Diatomaceous Earth Powder - 25 lbs.
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Backwash or Bump Cleaning

Like sand filters, a pressure gauge on the tank will let you know when it’s time to clean your D.E. filter. Typically, D.E. filters are backwashed just like sand filters. Some brands feature a bump handle, which lets you knock the used D.E. off the grids or fingers to clean.

Whether you backwash or bump the filter, you’ll need to add more D.E. powder after every cleaning. It can be difficult to determine exactly how much to add, so it’s especially important to disassemble and clean the filter by hand at least once a year.

How to Add New D.E. to the Filter

After you’ve cleaned your filter, rather than adding D.E. powder directly to the grids, you’ll get much better coverage if you add it through the pool’s skimmer.

As the D.E. passes through the filter, it will evenly distribute over the grids. You’ll need to wait a while before swimming to give the mixture time to fully integrate with the filter, so you may want to do this in the evening, and then run your pump overnight.

Illegal Backwashing

Some cities and towns appreciate backwashing as much as parents of small children do. Yours may have regulations specifying how to legally dispose of used D.E.

When it’s rinsed from the grids, D.E. powder can build up over time, creating a concrete-like residue that can clog storm drains or suffocate fish eggs.

Usually, you’ll be allowed to empty old D.E. into a disposable container and place it in the trash. Check with your local authority for specifics to ensure you don’t end up with a fine, and more importantly, don’t damage the environment.

Cancer Risk with D.E. Filters

Though D.E. is a known carcinogen, it has only proved cancer-causing in mice when inhaled long term.

Important: Safety first. Prevent accidental inhalation by wearing a chemical mask If you click this link and make a purchase, we earn a commission at no additional cost to you. when you handle D.E. powder. Also, keep children and pets away from the area when you’re working with D.E. powder, and from the area where it’s stored. Immediately clean up any spilled powder.

3M Chemical Mask - 2 Pack Price: $6.94
3M Chemical Mask - 2 Pack
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D.E. Filter Pros:

D.E. Filter Cons:

Size Matters

A pool filter and a pool pump go hand in hand. The filter can’t function without the pump to move water through it. And neither will work properly if the pump isn’t the correct size for your pool.

Before you settle on a pool filter, make sure you have the right size pool pump.

Optimal Filter To Fit Different Pump Sizes Chart

Filter Size

Filters are rated by gallons per minute (GPM) per square foot. The filter flow rate must be rated at least the same GPM as your pump, or higher. With pool filters, it’s best to err on the larger size so it can handle the power of your pump. A helpful rule of thumb is to choose a filter with at least 1 square foot per 10,000 gallons pool capacity.

Optimal Filter For Pool Sizes in Gallons Chart

Bargain shoppers beware. It’s nice to save money when you can. But off brands can come and go, leaving you searching for replacement products from defunct companies down the road. Buying a pool filter from a trusted manufacturer can save you headaches and dollars in the long run.

Best Sand Filters

If you’re looking for low-cost, low-maintenance filtration that won’t clog up quickly, four models stand out above the rest.

Hayward S244T ProSeries Top-Mount Sand Filter (Inground)

Featuring a weatherproof, corrosion-proof tank, the Hayward S224T ProSeries is built to last. It’s available in three sizes If you click this link and make a purchase, we earn a commission at no additional cost to you. and includes a multi-port valve.

You can get models with side mounts, if needed. Plus, you only have to backwash it every few months, depending on how often you use your pool.

Hayward S244T ProSeries Top-Mount Sand Filter - 24 in. Price: $335.89
Hayward S244T ProSeries Top-Mount Sand Filter - 24 in.
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Pentair Triton II Side Mount Sand Filter without Valve (Inground)

Created with ease of use in mind, the Pentair Triton II is the picture of simplicity. The pressure gauge is conveniently located and easy to read. Its swing-away diffuser gives you quick access to the sand If you click this link and make a purchase, we earn a commission at no additional cost to you. . And the combination sand/water drain makes winterizing a snap.

Pentair TR60 Triton II Side Mount Fiberglass Sand Filter without Valve Price: $536.99
Pentair TR60 Triton II Side Mount Fiberglass Sand Filter without Valve
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Hayward S210T93S ProSeries Sand Filter System (Above Ground)

Available in five sizes and built from tough thermoplastic, the Hayward S210T93S boasts features similar to the S224T ProSeries, but for above ground pools. Its seven-position flow valve If you click this link and make a purchase, we earn a commission at no additional cost to you. lets you easily compensate for low pressure.

Hayward S210T93S ProSeries Sand Filter System - 1.5 HP - 21 in. Price: $456.98
Hayward S210T93S ProSeries Sand Filter System - 1.5 HP - 21 in.
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Intex Krystal Clear Sand Filter Pump (Above Ground)

If you have an Intex pool, why not get a sand filter designed specifically for it? The Intex Krystal Clear has a 24-hour timer If you click this link and make a purchase, we earn a commission at no additional cost to you. so you can automate filter cycles. The six-function valve easily switches between filter, backwash, rinse, recirculate, drain, and close.

At the end of the season, it’s easy to quickly break down and store this filter through the winter. Plus, you’ll only have to replace the sand every five years or so.

Intex Krystal Clear Sand Filter Pump for Above Ground Pool - 16-in. - 110-120V with GFCI Price: $163.99
Intex Krystal Clear Sand Filter Pump for Above Ground Pool - 16-in. - 110-120V with GFCI
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Best Cartridge Filters

Want a finer filter media than sand, without the expense or labor-intensive maintenance? Four cartridge models do the job.

Pentair 160340 Clean & Clear Plus Cartridge Pool Filter (Inground)

Designed with the maximum filter surface area to clean your water more quickly and efficiently than other filters, the Pentair Clean & Clear Plus has an effective filter area of 320 square feet If you click this link and make a purchase, we earn a commission at no additional cost to you. . Internal and manual air relief make maintaining good water pressure easy. It filters 120 GPM inside a sturdy, injection-molded tank.

Pentair 160340 Clean & Clear Plus Cartridge Pool Filter - 320 sq. ft. - 120 GPM Price: $714.32
Pentair 160340 Clean & Clear Plus Cartridge Pool Filter - 320 sq. ft. - 120 GPM
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Jandy CS200 (Inground)

If you’re looking for a filter that fits in small spaces If you click this link and make a purchase, we earn a commission at no additional cost to you. , this one’s perfect. Jandy’s CS200 is available in four sizes, but the housing is a slim, tall cylinder made to fit in the tightest spaces. The thermoplastic body resists UV and weather damage like a champ.

Jandy CS200 Single Element Cartridge Filter - 200 sq. ft. Price: $545.00
Jandy CS200 Single Element Cartridge Filter - 200 sq. ft.
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Hayward C2251540LSS Micro StarClear Filter (Above Ground)

From a trusted name in the pool industry comes the Micro StarClear. This little Hayward filter is just right for above ground pools under 15,000 gallons If you click this link and make a purchase, we earn a commission at no additional cost to you. . It offers easy access to the cartridge for changes, and you can rotate the head so the pressure gauge and manual air relief valve are right where you need them.

Hayward C2251540LSS Micro StarClear Above-Ground Pool Filter Pump System - 40 GPM Price: $279.01
Hayward C2251540LSS Micro StarClear Above-Ground Pool Filter Pump System - 40 GPM
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Intex 28635EG Krystal Clear Cartridge Filter Pump (Above Ground)

If you’re an Intex owner looking for a cartridge filter, this is for you. Unlike other options, this filter uses disposable cartridges If you click this link and make a purchase, we earn a commission at no additional cost to you. . Maintenance is as convenient as turning the handy flush valve and popping in a new cartridge.

At the end of the season, dismantle and store it with your pool. If your weather is mild, its double-walled construction means you can just leave it up with no worries.

Intex 28635EG Krystal Clear Cartridge Filter Pump for Above Ground Pools - 1500 GPH Pump Flow Rate - 110-120V with GFCI Price: $57.37
Intex 28635EG Krystal Clear Cartridge Filter Pump for Above Ground Pools - 1500 GPH Pump Flow Rate - 110-120V with GFCI
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Best D.E. Filters

For just a bit more money and maintenance, you can enjoy the best filtration available by choosing a D.E. filter.

Zodiac DEV60 Jandy DEV Versa Plumb D.E. Filter (Inground)

Made from a durable composite that is UV and corrosion resistant If you click this link and make a purchase, we earn a commission at no additional cost to you. , the Versa Plumb is designed to stand the test of time. The pressure gauge is easy to read and includes an indicator that lets you know when to clean your grids. Easy grip handles and a large drain port make cleaning this filter a less daunting task.

Zodiac DEV60 Jandy DEV Versa Plumb D.E. Filter - 60 sq. ft. Price: $862.17
Zodiac DEV60 Jandy DEV Versa Plumb D.E. Filter - 60 sq. ft.
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Pentair 188592 Quad Cartridge Style D.E. Pool Filter (Inground)

Designed with easily removable cartridges, the Pentair Quad makes maintenance a little easier on you. It has four, large-capacity cartridges that provide loads of surface area so your pump uses less energy If you click this link and make a purchase, we earn a commission at no additional cost to you. to get the water just as clean as other D.E. filters.

The increased surface area also means it takes longer to clog, so you can clean it less often. It’s all housed inside a durable, fiberglass-reinforced polypropylene tank.

Pentair 188592 Quad Cartridge Style D.E. Pool Filter - 60 sq. ft. - 120 GPM Price: $744.57
Pentair 188592 Quad Cartridge Style D.E. Pool Filter - 60 sq. ft. - 120 GPM
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Hayward EC40AC Perflex Extended-Cycle D.E. Pool Filter (Above Ground)

If you’re looking for serious cleaning and low maintenance, look no further than the Hayward Perflex Extended-Cycle. Featuring a cool bump mechanism that allows the D.E. Flex-Tubes to clean themselves, this model means minimal cleaning time If you click this link and make a purchase, we earn a commission at no additional cost to you. . It’s designed to minimize resistance, so it can maximize efficiency at lower horsepower.

Hayward EC40AC Perflex Extended-Cycle D.E. Pool Filter Price: $292.00
Hayward EC40AC Perflex Extended-Cycle D.E. Pool Filter
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Hayward EC50C93S Perflex D.E. Filter Pump System (Above Ground)

Another model featuring Hayward’s Flex-Tube technology, the Perflex reuses D.E. so you won’t need to clean and refill as frequently as other D.E. filters. Like the Perflex Extended-Cycle, it decreases resistance to maximize pump efficiency, and lower energy costs If you click this link and make a purchase, we earn a commission at no additional cost to you. .

It also has a bump handle to make cleaning fast, a simple pump-to-filter union for fast closing, and a modular base that accepts a chlorine feeder.

Hayward EC50C93S Perflex D.E. Filter Pump System - 1.5 HP Price: $669.23
Hayward EC50C93S Perflex D.E. Filter Pump System - 1.5 HP
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The Best Filter is the One That’s Best For You

You can spend less money for less maintenance and less filtering. Or invest a little more up front for better filtering for the cost of more time and work. It’s really up to you what’s best for your schedule and your budget.

No matter what pool filter you choose, remember that keeping your water chemistry balanced gets you more than halfway to a clean pool. Stay on top of cleaning and maintenance, and your filter can last you for many years to come.

Happy Swimming!

Frustrated by adding chemicals and trying to keep your pool clear all the time?

We cut out all the fluff and confusion of pool maintenance and stripped it down to the bare bones in this easy-to-read illustrated digital guide.

Click here to learn more
The Art of Pool Care

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