In today's guide you're going to learn how to keep your pool nice and clean by choosing the BEST pool filter.
A filter is one of the most important pieces of gear you'll buy for your pool, so you want to get it right.
We'll go over:
- The different types to choose from
- How to find the right one for your pool
- Cleaning tips
- And the best filter for each type
Let's dive in to get started!
What does a pool filter do?
Here's the gist of how it works: every pool filter is used with your pool pump to circulate water through it and filter out the junk. It keeps your water clear of dirt, oils, debris and algae spores.
All this together is called the filtration system.
Typically, the larger the filter, the better it works, and it's okay to have a larger tank and a small pump if your pool size doesn’t require a large pump.
Just know there are three types: sand, DE (diatomaceous earth), and cartridge.
Types to choose from
Let's talk about the different types of pool filters, how much you can expect to pay for each, and their pros and cons.
Sand filters use a pool filter sand usually made with a base compound of silica, but sometimes with other materials such as crushed glass.
The sand is stored in a hollow tank equipped with a multiport valve, which have multiple positions so that you can set it to vacuum, filter, waste, or recirculate.
Basically, how it works is that your pump pushes water through the sand to catch debris and then back into the swimming pool.
Sand models, like DE, need to be backwashed frequently to clean out sand that plugs up the flow pips.
All that means is that you're basically sending the water through the filter in reverse to flush it out.
Sand types will clean your water to about 20 microns (a millionth of a meter), and they last up to 7 years.
A sand unit is for you if you'd like a very inexpensive option and don’t mind doing the backwashing.
DE models use diatomaceous earth matter, which is a naturally occurring sedimentary rock crumbled into a soft white powder.
It consists of a large tank with “fingers” or grids inside of it that are coated with the DE powder.
The powder filters the pool water much like sand, but does a much better job, removing debris down to 5 microns in most cases.
DE filters are considered the best on the market for keeping your water clean, but do require a bit more maintenance than the other types.
They need to be backwashed and replenished with fresh DE powder regularly, and if you have a DE unit with grids, those will also need to be taken out and cleaned by hand often to remove all the powder.
A DE is good for your swimming pool if you are concerned about keeping your water as clean as it can be and want a natural option to do so.
Cartridge units use replaceable cartridges to filter the water.
They remove debris down to about 10 microns and can be cleaned by simply hosing them off with a high-pressure hose, and they're the most energy efficient of all the filter types and also usually cost less than DE filters.
A cartridge is good for you if you have a small pool and would like a very low-maintenance filter.
How to find the right option for you
When you're looking for the right pool filter, be sure to follow these steps:
1. Understand your GPM
First you'll need to determine your pool’s GPM (gallons per minute) required to filter the water in the number of hours you run your pump.
So, if you run your pump 8 hours a day, for example, and have a 20,000 gallon pool, you will divide 20,000 by 8.
You'll then divide that number by 60 (number of minutes in an hour) to get 42 GPM.
If you don’t already have a pump, you will need to buy one capable of pumping 42 GPM.
2. Find the feet of head
This measurement only applies to in ground pools.
Feet of head is a term for the measurement of the average distance from the skimmers to the pump.
To get this number, you can measure the distance from each skimmer and main drain to the pump.
Add all those measurements together and divide by the number of skimmers and drains you measured for the average.
Most pools measure between 40 and 50 feet.
3. Determine your size
There are some complicated measurements you can use to get really accurate, but put simply, you need at least 1 square foot of filter area for every 10,000 gallons of water in your pool.
The reason you don’t have to narrow it down lower is because it is actually preferable to have a larger filter than your pump requires. This puts less strain on the pump.
So, when in doubt, go the next step up from the size of filter your pump manufacturer recommends.
Cleaning & maintenance tips
Even though sand filters are the lowest maintenance of all the filters, they still require a little cleaning now and then.
Over time, dirt and debris builds up in the sand, making it less efficient at cleaning the water passing through.
To clear this debris out, you will need to backwash these filters regularly.
The sand grains also wear down and become smooth after a few years, making it necessary to replace the material from time to time to keep it working best.
Like sand filters, DE models need to be backwashed now and then to remove dirt and debris build-up that can decrease cleaning efficiency.
But unlike sand units, DEs usually have removable grids that can be hosed off with a high pressure nozzle on a garden hose.
These should be cleaned once a month or so to keep them cleaning your water well.
Cartridge units don’t need to be backwashed. Instead, you remove the cartridges and either hose them off well or replace them.
Some cartridge systems are designed to use inexpensive disposable filters meant to be replaced often, while some use more durable cloth filters that can be washed and used over and over again.
Either way, you'll know it is time to be cleaned or replaced when you notice that it is not cleaning your pool water as well as it was.
You might even notice debris particles recirculating in your pool.
This Intex unit for above ground pools (click here to check the price on Amazon) uses disposable cartridges you simply rinse off or toss and replace every couple of weeks.
It's designed for above ground pools and contains the complete system, and comes equipped with a built-in timer so that you can set the operating times and forget it.
The pump is double-insulated to withstand extreme temperatures and made of durable materials.
It's also designed with an air release valve so that you can easily release air when it gets trapped inside the filter chamber.
And a sediment flush valve makes it easy to flush out debris from the bottom of the chamber.
The Hayward SwimClear (click here to check the price on Amazon) is designed to use reusable polyester cartridges, and can be removed and rinsed off with a garden hose as needed.
The tank is made of a durable reinforced material called Perma-Glass XL for extra long life, and is molded in one piece, reducing compromisable areas.
It comes equipped with a pressure gauge, air relief valve and single lock knob for security. The single knob lock eliminates the need for bolts or clamps which can weaken or wear with weather over time.
This type is made with a larger filtration element to filter more water efficiently and easily, and it can handle larger pools than some of its competitors.
The Clean & Clear Plus cartridge from Pentair (click here to check the price on Amazon) is designed with an injection molded tank for maximum durability, and has an effective area of 320 square feet.
The cartridges are made with large areas so that they efficiently and easily clean dirt and debris from the water.
It has a valve to release air manually in case of high air flow, an internal air relief system for normal circumstances, and a balanced tension control and hydraulic flow clamp and is corrosion resistant.
It's easy to clean with a drain clean-out port and comes with its own cartridges, which should be cleaned off with a high pressure hose once a month or so and replaced every couple of years.
This Hayward ProSeries (click here to check the price on Amazon) is made for inground pools with advanced full-flow technology.
This means it is designed with a large surface area for even water distribution so that it works fast and efficiently even with large amounts of water.
Its tank is made of a durable, corrosion-proof polymeric material and a patented 7-way multiport valve that can be set to waste, filter, winter, closed, backwash, recirculation, or rinse for maximum options.
The tank is self-cleaning and weather-proof for low maintenance, and its efficient filter means it uses less energy while filtering more water than other filters.
It's equipped with a large pressure drain for dummy-proof winterizing or preparing for having it serviced.
You can also get this model with a side-mount, if needed.
This Rx system for above ground pools (click here to check the price on Amazon) is effective, efficient and very low maintenance.
It’s designed with a molded tank in one piece that will fit with most any pump you have, and is also easy to set up and use, making it a must for the pool owner with little time to spare.
It has clearly labeled pieces and instructions for easy installation and multiple filter options for maximum performance.
The durable tank is made to withstand wear both inside and out and comes with a 3-year warranty in the event of defects.
It has a 6-position multiport valve for cleaning and running easily.
This Hayward system (click here to check the price on Amazon) includes the pump and filter tank.
The tank is made of a durable polymeric material and a 7-way multiport valve that can be set to filter, waste, closed, winter, backwash, recirculation and rinse, and is self-cleaning and weather-proof.
The rugged 1.5 HP PowerFlo Matrix pump is equipped with full flow technology to maximize filtration and increase energy efficiency; it does this by filtering the maximum square footage of water, evenly distributing it through the filter tank and causing the pump to run less.
It's designed to be easily and quickly installed and comes with all the components needed for a complete kit.
The Intex Krystal Clear (click here to check the price on Amazon) is made for above ground pools and is created to be easy to install, easy to use and efficient at filtering your pool water.
The sand medium is made to last up to five years for maximum worry-free, maintenance-free filtering.
It has a 24-hour timer for easy automatic operation and a built in GFCI with an automatic safety shut-off switch, and has a 6-way multiport valve to filter, backwash, rinse, recirculate, drain and close. And it’s designed with maximum flow rate to fit any size pool.
This system is virtually no maintenance except for replacing the sand every few years and will give you years of trouble-free use.
The tank is made of the most durable PermaGlass XL for strength and sustainability, and it's easy to use and service with its clamp system that gives you fast access for cleaning and maintenance.
It's equipped with an air relief valve and indicator gauge, and is uniquely designed with top-down backwashing technology, which makes it extremely efficient.
It's also made to clean large volumes of water with its large spacious grids and will remove debris down to 5 microns.
This DE from Hayward (click here to check the price on Amazon) removes debris down to two microns, making it one of the most effective filters on the market.
It's designed to maximize filtration and run with less resistance to increase efficiency and effectiveness for even larger pools, and is equipped with a Flex-Tube design to extend the amount of time between cleanings, recycling the DE powder with each use.
It's also self-cleaning for the best performance and very low maintenance.
This unit will clean you pool super fast and very well, ensuring that your family is swimming in the cleanest and safest water anywhere.
This Pentair Quad (click here to check the price on Amazon) uses four large filter cartridges that offer up the largest surface area possible: this means that is filters out a lot of debris very quickly with low resistance.
It also means you can go longer in between cleanings than other filters!
It's designed with its own unique flow pattern to increase filtration and cleaning ability, as its tank is constructed with a tough, weather and chemical resistant poly material reinforced with fiberglass so that it will last for years without defects.
The cartridges are also easy to remove and the assembly is easy to maintain.
This model will give you super clean water and low energy costs.
The filter you choose will depend on the criteria that you find most important, but it will also depend on the pump system you already own when narrowing down by size.
Remember to always go larger with the filter rather than smaller to cut down on energy costs and wear and tear on your pump.
Also, keep in mind the length of time you would like to go in between cleaning and repairs.
There are pros and cons to both and your local pool store or friendly pool guy (like me) can usually help you make the best choice.