How to Find and Buy The Best Pool Filter
Before you start shopping for a pool filter, you need to know the three types: Sand, DE (diatomaceous earth) and Cartridge. Each filter has their own pros and cons, which I’ll cover.
All three are used with a pool pump to push water through them. The term “filter system” refers to both the pump and the filter.
The pump pulls water from the pool skimmers and pushes it through the filter media inside the tank. The filter media traps dust, dirt, oils, hair, and other small particles which are referred to as microns.
How Big Is a Micron?
You hear the word “micron” a lot when shopping for a pool filter. To get a sense of how small a micron really is, I’ve created an illustration below. This will also come in handy when buying a robotic pool cleaner.
1. Sand Filters
Perfect for folks on a budget and want to spend less time maintaining the pool.
Sand Filters are large tanks filled with pool filter sand (the only sand appropriate for use in swimming pool filters is #20 silica sand, which is .45-.55mm in size).
The water from your pool is pumped through the sand bed inside the tank, filtering out any particles before returning the water to your pool.
Sand filters remove particles as low as 20 microns (see image above) which are caught in the tiny grains of sand.
Eventually, the particles build up inside the tank blocking the water from pushing through. This raises the pressure inside the filter tank, which is indicated by a pressure gauge on the multiport valve attached. When the filter has too much pressure, this is a sign it’s time to backwash.
Backwashing flushes out the filter by reversing the water flow out the backwash/waste port on a multiport valve.
Average Price of a Pool Sand Filter
The average price of an inground sand filter is $650. That does not include installation, which will vary depending on the pool.
The average price of an above ground sand filter is $250. Since the installing an above ground filter only requires hooking up some hoses, you should be able to do it yourself.
- Easy maintenance (Backwashing and Rinsing)
- The Filter Media (Sand) lasts 5 – 7 years
- Requires backwashing and rinsing
- Wastes water through backwashing and rinsing
- Filters down to 20-30 microns
- Creates the most pressure, making it less energy efficient
Alternatives to Using Filter Sand
The sand you use inside the filter is #20 silica sand, which is .45-.55mm in size. While the sand filter is the weakest of all the filters, you can increase its cleaning power with some filter sand alternatives, including ZeoSand and FilterGlass.
ZeoSand is made with natural mineral called zeolite which can trap smaller particles than normal filter sand. This improves water clarity, requires less backwashing, and uses 50% less ZeoSand. For example, if your sand filter usually needs 300lbs of sand, you only need 150lbs of ZeoSand.
Alternatively, you can use FilterGlass which is made with finely crushed recycled glass that’s smooth to the touch.
The major benefit of FilterGlass is its negative electrical charge. This attracts more positively charged particles such as iron and manganese. FilterGlass filters out particles at about 2-5 microns, and similar to ZeoSand, you can use less – about 20% less than normal filter sand.
If you want to stick to using #20 silica sand, you can add filter aids such as DE powder that can help improve sand’s filtering power.
Perfect for folks who have trouble keeping their pool clear and want to spend less time maintaining the pool.
Cartridge Filters are both energy efficient and cost-effective. They are large tanks (although not as large as sand filters) that house a cartridge filter, which is what the water is filtered through. There is no loose filter media like sand or DE used inside.
Cartridge Filters remove particles as low as 10 microns, and because of the large surface area, it has less resistance and performs well at slower speeds. Also, no backwashing – to some that’s a plus. Instead, the cartridge filter is removed from the tank and sprayed down with a garden hose. So technically, it requires a little more elbow grease, but it requires less cleaning and backwashing than a sand filter.
Quick Tip: to clean the filter, remove the lid, pull out the cartridges, and wash them individually making sure to spread and clean between the pleats. I recommend using a pressure nozzle on your garden hose.
How to Clean a Pool Cartridge Filter
Just like sand filters, however, the filter cartridges wear out and need to be replaced every couple years. However, even though cartridge filters seem pretty great, they are not recommended for very large pools because it would require multiple monster filter cartridges, which can be a real hassle to maintain.
Average Price of a Pool Cartridge Filter
The average price of an inground cartridge filter is $850. That does not include installation, which will vary depending on the pool.
The average price of an above ground cartridge filter is $450. Since the installing an above ground filter only requires hooking up some hoses, you should be able to do it yourself.
- No backwashing
- Performs well at lower speeds (perfect for energy-efficient variable-speed pumps)
- Filters particles as small as 10 microns (see image above)
- Helps conserve water
- More work than sand filters
- Need to replace worn filter cartridges about every three years
- Have to deep-clean the cartridges 1-2 times a year
Diatomaceous earth filters use a powdered form of fossilized exoskeletons to remove particles as low as 5 microns.
They are large tanks with grids or fingers inside that are coated with the D.E. Powder, which performs like sand, but better. Because of this, D.E. filters are the best of the three types of pool filter, but they are more expensive and require more maintenance.
Every time you backwash the filter, you need to add fresh D.E. Powder to your skimmer. There are two types of D.E. filters: bump and backwash.
The Bump Type of D.E. Filters
When the pressure inside the tank rises it means your filter is dirty and you need to “bump” the used D.E. powder off the grids, so you can make room for fresh D.E.
The most common is the Hayward D.E. filter that comes with fingers instead of grids and an official Bump Handle to perform this action. While this is the first type mentioned, it’s not the one I recommend.
The Backwash Type of D.E. Filters
I recommend buying a D.E. filter with grids and a multiport valve so it can be easily backwashed. Hopefully, you won’t have to backwash them at all because it can be a little tricky. Backwashing doesn’t get rid of ALL the old D.E. powder, so it’s hard to determine how much fresh D.E. to add.
Instead, it should be broken down and cleaned regularly. This means cleaning the grids and removing the old D.E. by hand, much like the maintenance required with a cartridge filter. Because some townships and counties restrict backwashing D.E. filters, this will help you avoid any fines.
Average Price of a Pool D.E. Filter
The average price of an inground D.E. filter is $850. That does not include installation, which will vary depending on the pool.
Since finding an above ground D.E. filter can be a challenge, I would suggest either a sand or cartridge filter for your above ground swimming pool.
- Filters particles down to 5 microns
- Fresh D.E. powder can easily be added through the skimmer
- The most expensive filter with higher maintenance costs
- D.E. Powder is carcinogenic in it’s powder form (in other words, don’t snort it)
- Grids need to be deep-cleaned once a year
- Some local towns and cities restrict backwashing
Which is Really The Best Pool Filter?
In my opinion, even though it’s the weakest in terms of filtering power, I think the sand filter is the best.
I believe in doing as little maintenance as possible so you can spend more enjoying and swimming in your pool. The sand filter requires very little maintenance in terms of cleaning and repairs.
However, if I had to pick my second favorite it would be a cartridge filter. They filter the water 2 times better than sand filters but require only slightly more maintenance. As long as you take care of your filter, it could actually perform better and last longer than a sand filter.
If you have a smaller pool (25,000 gallons and under), I would go with a cartridge filter. Any larger and I would absolutely invest in a sand filter.
What About a Pool Filter for a Commercial Pool?
If you’re buying a filter for a public pool (like in an apartment complex, swim club or hotel) then you should invest in a sand filter only.
While both DE and Cartridge filter the water better, that’s exactly the problem. They fill up with dirty quicker and require a whole lot more maintenance (and it can also get clogged a lot).
However, if it’s not possible to install a backwash line (or it’s restricted by the township) you should invest in a cartridge filter. But be warned, you will endure a lot more pool filter maintenance.
How to Choose the Right Size Pool Filter
If you already have a pump, and you’re just replacing the filter, you want to buy the right filter to fit the existing pump (assuming the pump is the correct size for your pool). Let’s determine if you have the right size pump with some simple math.
1. Determine the Right Size Pool Pump
We want to find the right GPM (gallons per minute) for your pool. First, we’ll find the GPH (gallons per hour) by taking the total amount of gallons in your pool and dividing it by 8 hours. For example, if your pool is 24,000 gallons, the formula would be:
24,000 (total gallons) ÷ 8 (hours) = 3,000 GPH (gallons per hour)
Now, since most pool pumps specs provide the GPM number, just divide the GPH by 60 minutes. Following the math above, that formula would be:
3,000 (GPH) ÷ 60 (minutes) = 50 GPM (gallons per minute)
So in this case, your pump needs to at least be able to pump 50 GPM. However, if you have an inground pool, you need to consider the average distance (in feet) from the pool skimmers and main drain to where the pump will be located; this is called the average Feet of Head.
Measure the distance in feet from all the skimmers and main drains along where the pipes would be underground. Add them together and divide by the number of skimmers and drains.
Now you’ve got the GPM and the Feet of Head. I know this is a long mathematical process, and you can even get more advanced, but it’s important to have the right sized pump. Here’s a chart to quickly find out what pump and filter size you need for the number of gallons in your pool.
2. Find The Right Size Pool Filter for Your Pump
It is a good idea to buy an over-sized filter for your pump. A larger filter will give you more surface area and allows longer periods of time between cleaning.
To make things simple, 1.0 sq ft (square foot) of filter area for 10,000 gallons of pool water. Or just use the chart below.
NOTE: If your pump pushes too much water into an under-sized filter, you risk damaging the inside of your filter.
One more thing to consider when buying a pool filter is the popularity of the brand. Throughout the many years of my time in the pool industry, I’ve seen people trying to replace parts for all kinds of filters. Some of which are no longer made because of companies going out of business or lack of demand. If you buy a rare pool filter, it will be extremely hard to find parts for. Trust me.
I recommend sticking to a few trusted brands like Hayward, Pentair, and Zodiac (Jandy).
The Best Swimming Pool Filters
Your filter is the lifeblood of your pool as it works hard to remove contaminants from your water so you can enjoy a pool that is clean, clear, and free of any debris. Choosing a filter can be tough, especially if you are new to pool ownership. These filters represent some of the best we have found and will do a great job keeping your pool clean all summer long.
Best Sand Filters
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Featuring a weather-proof tank, this sand filter is built to last. Designed for in-ground pools, the S244T from Hayward will make your maintenance schedule much easier and much less frequent as it only needs backwashing every few months, depending on pool use, of course.Buy Now On Amazon
This easy to assemble filter is perfect for any above ground pool owner. It’s made from all-weather thermoplastic that can withstand all types of weather. If you have low-pressure problems, it’s 7 position valve will allow you to adjust the flow even for maximum output even if your pressure is low.Buy Now On Amazon
A serious sand filter for the in-ground pool owner, this filter is designed with easy in mind. The gauge is easy to ready and conveniently placed, and all the parts are designed to be easily serviced and repaired if you run into a problem. Worried about the winter? Don’t be. This filter is easy to winterize so you can leave it connected all year long.Buy Now On Amazon
If you have an Intex pool, you will love this sand filter designed specifically for these types of above ground pools. It’s easy to setup and keep clean, and it even includes a handy 24 hour timer to help you set when your filter runs on your above ground pool. At the end of the season, you can quickly break down this filter and pack it away for the winter.Buy Now On Amazon
Best D.E. Filters
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If you are looking for serious cleaning and low maintenance, then look no further than the Hayward EC40AC. Featuring a cool bump mechanism that allows the DE flex tubes to clean themselves, your maintenance time will be very low with this filter. It also cleans your pool ultra fast, so you don’t have to worry about particles in your water right before you have that swim party.Buy Now On Amazon
This DE filter has four large capacity cartridges designed to give the most surface area possible to give your water a really good scrubbing. It’s designed to be easily removed so maintenance is easier than ever and you will even notice your energy costs drop as it moves and cleans the water faster than many other filters.Buy Now On Amazon
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This filter is designed to stand the test of time. It’s made from a heavy duty and durable composite that is designed to be UV and corrosion resistant. The pressure gauge is easy to read and even includes a clean and dirty indicator so you know when the time has come for you to clean it. With easy grip handles and a well thought out design, maintenance and service is easy reducing your costs in the process.Buy Now On Amazon
This modular and corrosion proof design is made for many different types of pools with a wide range of features. It’s also designed to save you money, as it will push more water per horsepower than other filters so you don’t have to worry about high energy costs because your filter and pump are running on your pool.Buy Now On Amazon
Best Cartridge Filters
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The Pentair 160301 is the perfect cartridge filter for in-ground pool owners. Designed with the maximum filter surface area to clean your water much more quickly and efficiently than other filters, you will never have to worry about your water quality ever again. With both internal and manual air relief, you will never have to worry about water pressure ever again. It’s easy to clean and service is simple, reducing not only your maintenance costs, but your energy costs as well.Buy Now On Amazon
Designed specifically for Jandy pumps, this filter is amazingly simple to connect and use. It includes a unique gauge to display when the filter is clean and dirty so you know when you need to remove and clean the cartridge. Its designed tough and made to last so you can connect it to your in-ground pool in a matter of minutes.Buy Now On Amazon
If you prefer cartridge filters and own an Intex pool, then this is the filter for you. Unlike other systems, the Intex Krystal clear is designed to be used with disposable cartridges. Simply flush the system with the handy flush valve and then replace the cartridge. It’s that simple. At the end of the season, it can easily be dismantled with your pool or thanks to its double insulation it can be left set up all year long depending on the weather.Buy Now On Amazon
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This filter and pump combo is perfect for any above ground pool owner. With its diversified sizes, you can connect this to almost any pool. While primarily designed for above ground pools, it has the flexibility to be used on in-ground pools as well. Its filter is designed to give you maximum surface area for high quality filtering so your water stays clean and clear without a lot of maintenance from you.Buy Now On Amazon
Any Questions? Are You Ready to Buy?
If you have an above ground pool, I recommend buying a sand (20 microns) or cartridge filter (10 microns). And if you are rocking a large inground pool, I would go with a sand filter.
If you’re up for the challenge of high-maintenance and a super clear pool, you can always go with the cleaning power of a D.E. filter, but don’t say I didn’t warn you about using all that extra elbow grease.
If you have any additional questions that this guide did not cover, please ask in the comments below. I will do my best to frequently update this guide as needed to answer all of your questions.
Oh…one last thing. Check out this neat infographic. If you like it (and you have an account), can you share it on Pinterest? Thanks!
The Ultimate Guide to Pool Filters Infographic
Spend Less Time Cleaning and More Time Swimming
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