The Best Pool Filters of 2021
Make sure your swimming pool water is fresh and safe to swim in with a pool filter.
By Allen Hayward
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Pool filters are responsible for removing harmful contaminants from your swimming pool water, such as bacteria and bugs. Even if you use chlorine to kill these contaminants, you still need a filter to remove them completely from the water. If you fail to filter these contaminants out of the water, then your pool water will have lots of debris and cloudiness in it.
Okay, so you know filters are important. But which one is the best for your pool? Don’t just look for the cheapest filter. You want to pick a filter that does a good job of blocking contaminants and is simple to maintain. Also, you’ll want a filter with a lot of longevity so it can survive multiple seasons.
To make the best choice, you need to learn about the filter options available.
The Pool Filter Size is Important
The pool pump and filter work together. You can’t have one without the other because the pump pushes the water through the filter. Also, the size of the pump must accommodate your pool. Don’t choose a filter until you choose the right pump size.
Size of Filter
The gallons per minute for each square foot is how filters get rated. The flow rate of your filter must match or exceed the gallons per minute of your pump. Just to be safe, it’s better to choose a larger filter in order to ensure that it can tolerate your pump’s power and force. To help you figure this out, the size of your filter should have a minimum of one square foot for every 10,000 gallons of water in your pool.
Be careful when you look for cheaper brands or bargains on these filter products. Sometimes you’ll find a defunct company’s brand when you go looking for replacement items. Always purchase your filter from a reputable manufacturer, even if you need to pay a little more. This will ensure that you’re getting a good quality filter.
The Most Reliable & Recommended Pool Sand Filters
The following sand filter models offer low maintenance and affordability.
Hayward Top-Mount Sand Filter S244T ProSeries Pool Filter
Why we chose it
The Hayward S224T ProSeries features a corrosion-resistant and weather-resistant tank. This type of construction is meant to make it last a long time. Three sizes are available, and a multi-port valve is included.
Side mounts come with certain models if you prefer them. The best part is that you only need to backwash the filter every couple of months. It all depends on how regularly the pool is used.
Pentair Side Mount Sand Filter without Valve Triton II Pool Filter
Why we chose it
The Pentair Triton II is simple and easy to use. You can read the pressure gauge with no problem because of its convenient location on the filter. The sand is easily accessible because of the swing-away diffuser. Winterizing is no problem because of the sand and water combo drain.
Hayward Sand Filter System S210T93S ProSeries Pool Filter (Above Ground)
Why we chose it
This is an affordable automatic pool cover pump which doesn’t require much work to operate. It is completely submersible and pumps out water when it gets up to 1/8” high. Included in the kit are a garden hose adapter and a 25’ power cord. These are the same accessories you’ll find included with the Wayne and Little Giant pool cover pumps.
The Ocean Blue can pump around 250 gallons of water per hour because it has a small motor. It is automated though, so you don’t have to monitor it while it’s pumping.
The Most Recommended Pool Cartridge Filters
Do you want a filter media that is finer than sand? Below are 4 cartridge models which don’t require much maintenance work and still give you a very fine filter media.
Pentair 160340 CCP320 Clean and Clear Plus Cartridge Pool Filter
Why we chose it
The Pentair 160340 Clean & Clear Plus features a filter surface range of approximately 320 sqft. This allows it to clean water faster in comparison to other filters on the market. It is easy to keep suitable water pressure with internal air relief. About 120 GPM is filtered within a firm injection-molded tank.
Intex 28635EG Krystal Clear Cartridge Filter Pump (Above Ground)
Why we chose it
Intex-branded above ground swimming pool owners will want this cartridge filter pump. You can use disposable cartridges with it, which is not something you see too often with other filter pumps. Maintenance is easy too because you can just twist the flush valve and put in another cartridge.
Once you’re ready to winterize, disassemble the filter pump and store it away until next summer. On the other hand, if you experience only mild weather in your location, then you can leave the 28635EG where it is because it’s constructed with two walls for lasting durability.
The Most Recommended D.E. Pool Filters
If you care about a high-quality filtration experience for some extra maintenance and cost, then go with a D.E. Filter.
Pentair Quad Cartridge Style D.E. Filter 188592
Why we chose it
The Pentair Quad has cartridges that you can easily remove. For this reason, maintenance won’t be a problem. There are 4 high-capacity cartridges with a lot of surface area. That way, the pump becomes more energy efficient when cleaning the water. On top of that, the huge surface area signifies that your filter won’t get clogged as easily either. This means you don’t need to clean the filter as often. All this is secured inside of a reinforced fiberglass polypropylene tank which is highly durable.
Hayward Perflex Extended-Cycle D.E. Filter EC40AC
Why we chose it
The Hayward EC40AC Perflex Extended-Cycle does not require much maintenance or heavy cleaning. There is a handy bump feature which allows for automated cleaning of the D.E. Flex Tubes. This greatly minimizes the cleaning time needed. Resistance is also minimized so that lower horsepower can have more efficiency.
Types of Pool Filters
You must learn about the options available before you choose a filter. There are 3 filter types that you can select from; Diatomaceous Earth (D.E.), Sand, or Cartridge. The type of filter you choose will determine the filtration rate, price, how it’s cleaned, and how often you’ll need to replace it.
If you’re like most pool owners, then you’ll want an inexpensive filter which doesn’t require much of your time to maintain. If that sounds like, you, then choose the sand filter for your pool. Sand filters don’t usually clog as much as other types of filters. This makes them ideal for larger swimming pools.
When your pool pump is activated, it pulls water toward it from the skimmers. Once the water reaches the pump, it gets pushed into a huge filtration tank that is filled with sand. This is usually #20 silica sand. Any particles that are at least 20 microns will be grabbed.
Each sand grain is rather prickly. From a microscopic viewpoint, a sand grain has several rough edges surrounding it. These edges are what give sand particles the ability to grab debris as it tries flowing through the filter.
After a few weeks or years, the edges of these sand particles get worn down because of erosion. If they get worn down enough, the edges will be smooth instead of rough. This will make them incapable of capturing debris. Plus, particles will get stuck in the sand and gradually accumulate until the filter is no longer functional. Smaller particles may get trapped more easily, though. Unfortunately, the water flow won’t be adequate enough as it tries passing through the filter. This reduces the efficiency of the filter.
On the side of the filter, there is a pressure gauge which lets you know when the internal pressure increases. If you receive this alert, it means the filter needs to be backwashed. This is where the water flow is reversed by the filter, causing all the debris to be flushed out.
Since the silica grabs particles which are at least 20 microns, you need to pay attention more to the chemistry of your water. If you don’t have an adequate amount of sanitizer in the water to destroy smaller bacteria that are 2 microns, then a sand filter certainly won’t trap them. As a result, the bacteria will exist in your pool water to cause people great sickness.
Alternatives to Sand
Most sand filters use #20 silica media. If the sand is replaced or you backwash the filter, then D.E. powder can be added afterward. This will boost the efficiency rate of filtration.
Below are two alternative choices for replacing the #20 silica if you want.
Zeolite is the mineral that ZeoSand is made from. Compared to the standard sand of a filter, you can get away with using half as much of ZeoSand in the filter. Since ZeoSand is shaped like a crystal, it is easier for it to catch tiny contaminants. This enables the water to be clearer, and you won’t need to backwash as much. You should get a lifespan of roughly 5 years out of ZeoSand, which is about the same lifespan as silica.
Filter glass is recycled glass that is crushed. Since the crushing is done in a fine way, there is no risk of cuts because it feels quite smooth. There is a negative electrical charge coming from the glass, causing it to attract iron, manganese, and other positively charged particles. Because of this, you can reduce the filter glass amount needed by around 20%. Meanwhile, it can filter debris particles which are only 5 microns in size. Compared to pool sand, filter glass has a 3 times greater longevity.
Sand is good for 5 to 7 years; replace after that.
Additives can be used to boost the efficiency of the filter.
Filter efficiency reduces by building pressure
Water is wasted from rinsing and backwashing
20 microns is not very effective compared to the other types of filters
Cartridge filters may cost more than sand filters, but they’re more effective and simpler to maintain if you have a smaller pool.
The tank has a plastic cylinder inside of it. Each end of the cylinder has a cap on it. Pleated polyester media surrounds it too. When the pleats of the tank receive the water flow, the filter captures small debris that is 10 microns or more. Once the water is successfully filtered, the newly cleaned water flows to the pool again.
Cartridges cost less and will save you money on energy. After enough contaminants are collected in the filter, you will need to clean it out. You can do backwashing, or you can take the cartridge out of the tank and use a hose to spray away all the dirt and debris that is stuck on it.
Periodically, use a filter cleaner to spray down the filter. Then, more regularly, soak the filter in a cleaning solution that is formulated for filters. Diluted muriatic acid is often used as the cleaning solution too. Even though this will require more effort than backwashing the filter, you’ll at least conserve more water.
Contaminants that are 10 microns or more can be filtered.
You don’t need to backwash; saving you more water.
Low speeds are fine; use with a variable-speed pump.
2 to 3-year longevity
Requires additional work compared to sand filters
Deep cleaning needed up to 2 times annually
Diatomaceous Earth Filters
Diatomaceous earth filters can block very tiny particles as small as 5 microns. The downside is that these filters require more maintenance. They’re also more expensive too.
The tanks of “D.E.” filters feature special grids which have a white powdery coating. The contents of this powder include the fossilized remains of diatoms, which are small aquatic lifeforms. Silica is also found in these fossils too, but D.E. filters are still different from sand filters. You can find this white powdery substance in many common products like toothpaste, cosmetics, pest control, and more. However, this doesn’t mean you can fill your filter with pest control powder as an alternative. D.E. has been treated with heat, so this allows it to be a filtration media.
The tank of the D.E. filter has a pressure gauge which tells you when the filter should be cleaned. Usually, you can backwash D.E. filters the same as you would with sand filters. There is a bump handle on certain filter brands which allows you to remove the D.E. particles from the grids without having to backwash. But regardless of whether the filter is bumped or backwashed, additional D.E. powder should be added each time you clean it. You may have trouble figuring out the amount to add. Because of this, you should disassemble the filter manually and then clean it a minimum of one time per year.
Adding More D.E. To Your Filter
Once the filter is cleaned, you should add more D.E. powder to the skimmer of the pool instead of to the grids.
Add the D.E. to the water until it appears slurry and creamy.
The pool pump should be running, so activate it if you must.
The mixed solution should slowly get poured into the skimmer.
When the D.E. enters the filter, the particles will spread evenly on top of the grids. Don’t swim until the mixture has been given some time to completely assimilate itself with the filter. One strategy is to apply the D.E. in the evening time when no one is swimming. Keep the pump turned on throughout the night.
Caustic chemicals are not needed to clean.
D.E. powder goes in the skimmer.
You can filter contaminants that are 5 microns in size or more.
More cleaning work is required each year
Must replace grids after 2 or 3 years
Pool Filter Troubleshooting
Your filter must remain in great condition if you want it to do a good cleaning job. However, there are some problems that filters tend to run into. You need to recognize these problems for what they are. This makes it easier to troubleshoot your filter and repair the problems wherever they are.
Does your filter have water dripping anywhere from it? If you hear the dripping or see a little puddle somewhere around it, then you may have a leak in your filter.
The water level of your pool won’t be too affected by a leaky filter. But still, you should investigate the problem by locating the leak and then fixing it before it gets worse. See if there are holes in the tank of the filter. Once you spot a hole, patch it up if you can. This is only a temporary solution, though, because the patch is not going to last for a long time. You’ll need to replace the entire tank as soon as you can. The patch only buys you some time.
With split-tank filters, look for leaks in the belly area. Take off the band from it and look at the O-ring to see if it’s worn out or clogged with debris. Replace the O-ring if it’s worn out. Pool gasket lubricant should be added to assist in the sealing process and to sustain the hydration of the ring. This increases its longevity.
The flow rate of your filter may be in trouble if it runs in small cycles only, whether the pool is being used or not. Perhaps you have an excessively high pool rate because your pump is too powerful to be handled by your filter. You’d need a bigger filter to fix this issue as long as your pool can accommodate it.
If you have the proper size filter, then you should backwash it for a longer time. As you backwash the filter, keep it going until you can clearly see the water in the glass. Several minutes may be needed for this process to be completed.
Another reason for these shorter cycles may be due to debris or algae building up in the filter, which is clogging it. That is why you must thoroughly clean your pool filter. If it looks worn out, then replace it.
Pool Filter Material
After you backwash your pool, you may see some of the filter material in the water. It doesn’t matter which type of filter you’re using either. On the other hand, if you see filter material in the water and you have not backwashed, then you should be concerned.
Inspect the bolts which secure the filter to the pool. If the bolts are loose, then particles may find their way out of the pool. If the bolts are not loose, then check for other reasons why this is happening.
When dealing with a D.E. filter, the grid fabric may have a tear in it. Either that or the grid manifold may have a crack. In that case, the manifold should be replaced.
Water Pressure Issues
Inspecting the pressure gauge needs to be done along with other pool maintenance tasks. The performance of your filter will be affected if you have water pressure issues.
Low water pressure will cause the system to get clogged in an area before the pool filter. High water pressure will cause the system to get clogged in an area after the pool filter. You must check all areas of the filtration system for blockage. If you find debris in certain areas, then clean it out. Once the filter is completely clean, take a look at the return valve because it should be opened entirely.
You can buy a cheaper filter which requires less maintenance but also filters less. Either that or you can spend more money on a better filter which requires more time and maintenance. It all depends on your budget and schedule. In any event, the chemistry of your water must always be balanced. If you can do all these things, then you’ll have a long-lasting filter.