Why Is a Pool Filter Essential and How to Select the Right One for Your Home

Want to know the importance of pool filters? Read this article and learn how it keeps your swimming pool clean and safe for everyone.

It’s common knowledge among swimming pool owners that pool filters are essential. And if you’re now planning to build your first swimming pool, you may feel hesitant in buying one since filters can be quite pricey. It might also be confusing which filter to select due to the number of options in the market.

But don’t worry, we’ve got your back on your venture. Quoting Aristotle, a Greek philosopher, “Those who know, do. Those that understand, teach.” Because we understand, it’s our duty to teach you the importance of having pool filters.

So in this article, we’re gonna talk about why bother installing a pool filter, the different types, and what factors you should consider when choosing one.

Why a Pool Filter Is Essential

With the prices of pool filters ranging from $500 to $2,000, you might feel like it’s too much to buy one. On top of that, there’s still other swimming pool equipment that you’ll need to buy. So for us to look beyond the price, we need to understand the important role that it plays. 

A pool filter belongs in the filtration system of your swimming pool. The basic parts of this system are the pump, the filter, the pipes, and sometimes there’s a heater integrated into it.

The pool water circulates into the filtration system through the force applied by the pump. And as the water circulates, the filter removes dirt, debris, and other particles that contaminate the water. This continuous filtration ensures that your pool remains clean and clear. [1]

That is why, even if pool filters are pricey, they remain an absolute necessity in pool maintenance. If you’re still not convinced, just think about the cost comparison of constantly replacing the pool water in contrast to just needing to replace the water in around five years or so.

Now that we’ve established that pool filters are essential, let’s move forward to the types of filters available in the market.

Sand Filters

As its name implies, a sand filter uses sand as filter media. Using sand for filtration systems is one of the oldest and most common methods used. In fact, a sand filter was used for water treatment during the start of the Industrial Revolution. [2]

Basic Parts and Functions

Pool Filter - Sand

A sand filter has six basic parts, each has its own role in the maintenance process. Take note that these are basic parts and some manufacturers may have additional parts depending on what they have designed. [3][4]

  • Filter tank 
  • This part is the casing that holds all the other parts together. Normally, it is solid one-piece cylindrical metal or polymer made to withstand the pool filter pressure and corrosion.
  • Sand filter media
  • This is what pool filters or traps the contaminant particles in the swimming pool water. Sand is what usually fills up the entire tank.
  • Valve 
  • This controls the direction of the water flow in a sand filter. Backwashing of the sand is done by using this valve. And there are two types of valves used in a sand filter, multiport valves, and slide valves.
  • Diffusers
  • This part is inside the filter at the top portion and sprays water inside the tank. Diffusers ensure that the incoming water from the pool is evenly distributed to ensure that the sand filter is efficient.
  • Laterals
  •  This part is located inside and at the bottom of the filter. Laterals serve as outlets for the filtered water.
  • Air Vent/Relief
  • This part relieves the air as the water pumps inside the filter. Compressed air can be dangerous for the filtration system.

Advantages and Disadvantages

The main advantage of sand filters is that they are very cost-effective. Meaning, if you’re on a budget and you still want to keep your swimming pool clean and clear, you might be better selecting this type of filter.

Although budget-friendly, sand can only filter up to 20 microns which can leave some of the smaller organisms in the pool. But can be easily dealt with by using clarifiers and other chemical treatments.

Cartridge Filters

This type of filter uses a thin porous membrane, usually reinforced polyester, as its filter media. The membrane is wrapped around cylindrical cartridges, hence its name. [5]

Basic Parts And Functions

Pool Filter - Cartridge

A cartridge pool filter has four basic parts, each with its own roles. These are basic parts and some manufacturers may have additional parts depending on their design. [5][6]

  • Filter Body
  • This part holds all the parts together and is designed to withstand pressure and corrosion. The pipe connectors are also found on the body.
  • Plates / Manifolds
  • An assembly placed inside the filter body holds the filter cartridges in place. These also serve as connectors and outlets for the filtered pool water.
  • Filter Cartridge
  • This is what filters or traps the contaminant particles in the swimming pool. Cartridge filters are usually clustered in a group or two or 4 inside the filter.
  • Air Vent/Relief
  • This part relieves the air pressure inside the pool filter.

Advantages and Disadvantages

One of the advantages of using cartridge filters is that they can filter out smaller particles when compared to sand filters. Cartridges can filter out up to 10 microns meaning.

Although it can filter better, cartridge pool filters are pricier than sand filters. So if you’re on a tight budget, you might not opt for this option.

And unlike the sand and DE filters, you can’t backwash cartridge filters. So cleaning it is more tedious since you’ll need to disassemble and clean manually.

Diatomaceous Earth (DE) Filters

This type of pool filter uses fossilized remains of tiny aquatic organisms called diatoms, hence its name. These powdered fossilized remains act like a sponge that absorbs small particles.

Basic Parts and Functions

Pool Filter - DE

A DE filter has 4 basic parts. Kindly take note that these are just the basic parts and every manufacturer has different designs. [7][8]

  • Filter Body
  • This part holds all the parts together and is designed to withstand pressure and corrosion. The valves, air relief, and gauge are also found on the body.
  • Valve 
  • This controls the direction of the water flow in a DE filter. Backwashing of the cartridges is done by using this valve. 
  • Plates / Manifolds
  • An assembly placed inside the body holds the cartridges or septums in place. This also serves as a connector to the pipes outside the 
  • Cartridge / Septums
  • The cartridge or septum is the container of the DE powders. This holds the powders in place during pool operation.
  • Air Vent/Relief
  • This vent relieves the air inside the pool filter. 

Advantages and Disadvantages

The main advantage of using DE filters is that it has the best filtering abilities-it can filter out up to 1 micron. That can filter even small bacterias.

But of course, with great filtering power comes a great price. Out of all the filter types that you can use, DE filters are the most expensive. Aside from that, every time you backwash you’ll need to add in DE powder. So if you’re working on a tight budget, this might not be for you.


In summary, a pool filter is essential to keep your pool clean and clear. Nobody wants to swim in dirty muddy water right?

Although there are many factors to consider when buying a pool filter, selecting the best-suited pool filter for you mainly depends on your budget and the filtration capacity that you want. 

If you’re aiming for the cheapest pool filter, then you can consider buying sand filters. But if you’re willing to spend more just to get the best filtering ability, then diatomaceous earth filters might be more suited for you.

Quoting Anne Schaef, an American author: “Good health is not something we can buy. However, it can be an extremely valuable savings account.” True to this, don’t be afraid to buy equipment that will keep you and your family healthy in the long run. Remember, lost health can be hard to recover.

Check out some interesting reads for pool owners and those who love them.


  • [1]https://www.who.int/water_sanitation_health/bathing/srwe2full.pdf
  • [2]https://sswm.info/sswm-university-course/module-6-disaster-situations-planning-and-preparedness/further-resources-0/slow-sand-filtration
  • [3]https://www.pentair.com/content/dam/extranet/pentair-pool/commercial/manuals/filters/triton-instructions-english-spanish-french.pdf
  • [4]https://www.pentair.com/content/dam/extranet/pentair-pool/commercial/manuals/filters/triton-instructions-english-spanish-french.pdf
  • [5]https://hayward-pool-assets.com/assets/documents/pools/pdf/literature/SwimClear-SellSheet-LITSCME17.pdf
  • [6]https://www.pentair.com/content/dam/extranet/pentair-pool/residential/manuals/filters/clean-and-clear-plus/clean_and_clear_plus_install_guide_english.pdf
  • [7]https://www.pentair.com/content/dam/extranet/pentair-pool/residential/brochures/pool-filters/easyclean-de-filters-brochure.pdf
  • [8]https://hayward-pool-assets.com/assets/documents/pools/pdf/manuals/Pro-grid-DE2420.pdf
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About the author

Brian Anderson

The rather dry pool world out there is in need of some passion to make it shine. With the help of my son Ruben and his wife Maria our mission is to help you create the favorite spot of your house - your pool.

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