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Pool filter media: understand how your pool will thank you
Welcome to our pool filter media guide! Whether you’re already a pool owner, or about to become one, it’s important to know about different types of filtration systems. Today we’ll talk you through a common one, media filters, also called “sand filters” in the past.
If you’re wondering how to run your above-ground or in-ground pool with the best media filter, as well as what type of media to use, stay right here.
In this guide to media filters, you’ll find:
Let’s get filtering.
What is a pool filter media?
Pool filter media is one of three types of filter that you can have for your pool. The others are cartridge filters and DE filters. Pool filter medias are famously efficient, low-maintenance and inexpensive, making them a popular choice for Kiwis all around New Zealand.
They don’t need regular cleaning. Just change the media every five to ten years, depending on the media in the filter. This way, this miniature indoor beach will keep your swimming pool waves clean.
Swimming pool media filters are used for the same purpose as other swimming pool filters. Powered by the pool pump, they are tasked with cleaning your pool by filtering out very small pieces of debris.
Great water circulation plays a key role in achieving this.
How do pool filter medias work?
In a nutshell, pool media filter caughts the debris in your pool by trapping them on the surface of the media. The way the media traps the dirt depends on the type of media that is in your pool filter. Some media rely more on attracting the dirt from the water and some rely more on trapping the dirt.
Research into filters about 20 years ago found that as the water travels through the filter, it’s cleaned by a combination of two methods: mechanical entrapment and electrostatic attraction.
- mechanical entrapment is when the media captures the dirt in pits and hollows on the surface of the media. This is how it was believed sand filters worked. But research showed that this was not the only process at work.
- electrostatic attraction is when dirt is attracted to the surface of the media by an electrostatic charge created as the water passes over the media surface. This is a bit like the charge you get when you walk on a carpet while wearing socks.
The harder the media is, the more of the electrostatic charge is created by the water passing over the media. This charge is a very effective way of trapping the dirt from the pool water. Regardless of your media type, the more water that passes through the media filter, the dirtier the media gets.
In the beginning, this actually helps the filtration process as the sticky dirt acts as another filter layer. After a while though, dirt builds up in the filter and it isn’t all removed by backwashing. This makes the media less efficient, and you may need to replace it. We recommend that you replace sand and zeolite about every five years, and glass every ten years.
Hands-on pool's media filter, literally: the multiport valve
The part of the media filter that you will use the most is the multiport valve (MPV).
The MPV is usually mounted on the top of the filter tank, but it can be mounted on the side as well. This is what directs the water through the filter. It has six positions:
- filter: directs the water down through the media and then back to the pool.
- recirculate: the water goes straight back to the pool, missing the media.
- waste: in this position the water flows straight down the backwash line to the pool drain, missing the media.
- backwash: the water is directed up through the media and flushes the dirt down the backwash line.
- rinse: used after backwashing to flush any debris out before going back to filter.
- closed: water flow is stopped.
Whenever you need to change the setting of the MPV, you must turn the pump off first. This will help to prevent damage to the valve.
And that’s it, simple!
What kinds of media can I use as filter?
Pool filter medias need specific types of media, so make sure you get the right kind.
You can find a few options below. If you’re not sure which one you’d like to go for, get in touch with us. We’ll happily talk more about it with you and find the best one for your pool.
Remind that after you’ve installed this new toy, just like everything, it’s going to need cleaning sooner or later. You can read a bit more about the backwashing process in our Ultimate guide to pool cleaning.
Glass media
With a low environmental impact, glass is a great choice. Like the name suggests, it’s made from glass, but is still pretty smooth to the touch. It’s made from recycled glass, which reduces landfill waste.
The glass particles are all slightly different sizes, which makes it very effective at capturing the tiny bits of debris that make it into your filter. This is a great benefit.
Glass is harder than sand, so it creates more charge and attracts more dirt from the water, while capturing less of the dirt through mechanical entrapment. Over the life of the filter, glass will give you the best water quality.
Silica sand
Silica sand is mined, not manufactured: silica is normally graded river sand that’s been dredged up.
It used to be a popular choice for pool filter sand because its rough surface makes a great net for catching debris from the water.
Sand uses a mixture of both cleaning methods (electrostatic charge and mechanical entrapment). But overall, it doesn’t filter as well as glass does, because it doesn’t produce as much of an electrostatic charge.
Zeolite
Zeolite is a bit different to other types of filter media. This one is mined from volcanic rock minerals. They are relatively soft and rely mostly on trapping the dirt by mechanical entrapment in a sponge-like structure. When Zeolite is first used in a pool filter, the water quality is amazing.
However, once the centre of the sponge-like structure of the Zeolite is filled up, the amount of dirt trapped becomes pretty much the same as sand.
It’s like your kitchen sponge: no matter how much you clean it, you can’t get all the dirt out of the centre of the sponge and it eventually needs to be replaced with a nice new sponge.
How long does the media filter last?
Usually it lasts five to ten years. Fresh sand for sand filters has rough edges and, as we know, this efficiently captures and holds back micro debris passing through the sand.
You might start to notice the difference in your pool:
- have you been using more pool shock than usual?
- does the water seem cloudier more often?
- does the pressure on the pressure gauge not drop after backwashing like it has before?
If this is the case, it has likely become more difficult for water to pass through the media.
Alternatively, the water is instead cutting straight through a weathered hole. This means that your filtration has dropped to nil because the water is taking the path of least resistance through the filter.
When this point is reached, it’s a good time to change the media in your filter and start again with those rough and ready edges!
Don’t forget, you can chemically clean your media once a year, which will give you a much longer life. For that purpose, consider using Focus filter degreaser.
Finding the most suitable pool filter media for your needs
There are many types of media filters for swimming pools, so we’ve narrowed our recommendations down to our favourites.
It’s important to consider what filter size you need for your pool, taking into account whether it’s an above-ground pool or an in-ground pool and the size of your pool pump.
We recommended the Hayward Pro Series Sand Filter. This media filter is suitable for above ground and in ground pools of all sizes, spa pools and water features. Besides, Pro Series Filter is great for sparkling, crystal clear water using the latest technology.
Looking for the most updated product? In this case consider also the EcoClear Glass which takes it one step further.
The alternatives to pool filters media
Here in New Zealand, one of the most common alternatives to a sand filter is a cartridge filter. Both types have their benefits, so let’s have a look at their pros and cons.
Media filters | Cartridge filters |
|---|---|
| catches particles down to 5 microns in size, depending on your media type. | needs cleaning more often (at least once a month) because of how effective it is. |
| very easy to maintain: backwash twice a month or so to clean it. | very convenient: easy replacement and maintenance. |
| shouldn't need the media replaced for about five to ten years. | lasts three to five years. |
| historically proven filtration method | can be more effective than some media types, catching debris 10 microns in size (smaller than media filters can). |
Media filters should last longer, if you take care of them properly.
Get your pool filter media today!
The importance of pool filter media cannot be overstated when it comes to enhancing the well-being and leisure time of pool users (and the owner!). By efficiently removing contaminants and maintaining crystal-clear water, pool filter media ensures a clean and inviting swimming environment, promoting not only physical health but also mental relaxation.
With a properly functioning pool filter, owners can spend less time worrying about maintenance and more time enjoying their pool oasis, basking in the serenity and joy that a pristine pool brings. So, invest in high-quality pool filter media, sit back, and let the technology do its magic, transforming your pool into a haven of rejuvenation and endless fun.
Questions or comments? Chat with us, we will be glad to assist you.
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Hey! I'm Adrian, founder and pool expert here at Dolphin Pacific. I love spending time with family, fishing, and have been known to brew my own beer.
