How Often Should You Replace Your Swimming Pool Filter?

Your swimming pool filter is like the kidney of your pool: it filters out the debris and unwanted nasties, leaving you with fresh, clean water.

Making sure your filter is working effectively is hugely important, regardless of whether you have an indoor swimming pool or a small, above-ground pool for summer. In this guide, we look at when you should be replacing your filter system and how you can keep your water cleaner for longer.




How Do Pool Filters Work?


Pool filters are really simple. A pump pushes water through a tight space that only allows clean water through, collecting any small particles of dirt and removing them from the water.

Types of Swimming Pool Filter

There are various types of filter available for swimming pools, and which is right for you often depends on the type and size of pool you have.

Generally, swimming pool filters are divided into three categories:

  • - Cartridge Filters
  • - Sand Filters
  • - Glass Filters

A small pool, like a temporary above-ground pool or hot tub, will often use a filter cartridge. This filter is less effective than sand or glass but is the simplest and cheapest option, making it perfect for smaller pools.

A filter cartridge is typically round like a barrel and made from polyester cloth or corrugated paper. Swimming pools with this filter will push water into the cartridge, which will trap any dirt.

Most swimming pools, however, opt for filter pumps which employ sand or glass media. Here, the filter is part of the pump system itself, filtering any dirt as it passes through and returning clean water to the pool. One especially popular model here is the Lacron sand filter

Sand filter media operates by allowing water to pass through a canister containing sand (usually silica or pool-grade, not just from the beach!). The smaller water particles will pass through, but the larger particles get stuck, providing clean water.

Glass filter media works in much the same way. However, glass filter media tends to be more efficient and can capture particles around 1/4 of the size of sand filters. Hence, they tend to be more effective.

Clean swimming pool water

How Long Do Pool Filters Last?


Your swimming pool pump system can expect to pump 60-70,000 gallons of water every 8 hours. That’s a lot of work!

Like all things, swimming pool filters become less effective with age! When the filter has passed its prime, it will get clogged, dirty, and become ineffective.

How long your pool filter will last ultimately comes down to how much dirt it needs to clean. Assuming you properly maintain your swimming pool, you should expect the below timescales on average:

  • - Filter Cartridge – approximately 2,000 working hours, usually around 2-4 years.
  • - Sand Filter Media – around 3-7 years
  • - Glass Filter Media – about 7-15 years

When to Clean your Pool Filters


If your pool filter’s quality has decreased, it may not necessarily need replacing. All filters need regular cleaning to ensure they can work to their full capacity.

If you’re using a cartridge filter, remove it and rinse it off thoroughly with a stiff brush and hose, and use a specialist cleaner if available. Aim to do this once a week for the optimal longevity for your filter.

To care for a glass or sand-based pump filter system, you perform a procedure known as backwashing. Most pump systems will come with a backwash option, allowing water to run through the opposite way to before, lifting clogged dirt from the filter.

You should look to backwash your pool filters whenever the pressure has risen from its normal levels by around eight-to-ten psi. During heavy use, this will happen every week, and sometimes more frequently than that.

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How to Know When Your Filters Need Replacing


As mentioned above, some symptoms of a poorly-working filter can be due to uncleanliness. However, there will often come the point when cleaning your filter isn’t enough and it needs replacing.

Here are some of the signs to look for when considering a filter change:

Rapid Underperformance

If your filter gets clogged or stops cleaning more frequently than expected, even with frequent backwashing, it may have lost its quality.

Use-By Date

Filter cartridges will often come with a use-by date due to their design. However, all filters have a predicted lifespan. If this is passed, then it may be best to replace the filter.

Damaged Filter

This point applies to filter cartridges, which can tear over time. If this happens, you need to replace the filter.

Two swimming pool pumps with clean filtered water

How Often Should You Change Your Pool Filter?


You should change your pool filter whenever it loses its quality, has passed its expected lifespan or shows signs of damage. Often, symptoms will start to appear every five years, but the timescale can be anywhere between yearly and every 15 years.

When to Change a Sand Filter

Sand filters will often be able to perform for around three-to-seven years, depending on use.

If you frequently clean and backwash your filter and only use the pool seasonally, you can expect to replace it after at least five years. While sand filters can be good for a few more years, we recommend replacing your media at this point to maintain a healthy pool system long-term.

When to Change a Glass Media Filter

Glass filter media is known for its longevity – if well cared for, it might not need repacing for over a decade!

Glass filter media can last for way beyond the timespan of sand media. However, we also recommend replacing them every five years to keep your pool systems working efficiently.

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When to Change a Filter Cartridge

Usually, you can determine visually if your filter cartridge is working or not, but it’s always recommended to change it once its use by date has passed. This date is often after one or two years, depending on the brand. If you see a tear in the filter, it will need replacing.

Pool Filter Clogging Too Quickly? Tips for Longevity


Ultimately, the lifespan of a filter depends on how much dirty water it needs to clean. If you want to increase your filter’s longevity, make sure you care for your pool regularly and follow cleanliness rules.

Managing Pool Water Quality

The most important thing is maintaining the right chemical balance daily. Having the correct chemicals will stop algae from forming and help deal with other dirt and debris, putting less strain on your swimming pool filters.

Note that while clarifiers and similar products can make your swimming pool look clean, they can lead to your filter becoming more clogged. In the end, there’s no substitute for frequent chemical management.

Clean Swimmers

The more usage the pool has, the dirtier it’s likely to become.

Swimming pool users will bring contaminants with them into the pool, which ultimately ends up in the filter. These can include body oils, shampoos, drinks and more.

If you want to care for your swimming pool, you can take steps to minimise the impact people have.

  • - Shower First – Taking a shower before going in the pool will remove some of the contaminants that end up in the filter.
  • - No Food or Drink – encourage people to enjoy any food or drink before or after the pool, not during their swim!

Caring for Your Pool Filters When Out of Use

Another thing to consider is what happens to your filters when the pool isn’t in use. If you use your small swimming pool seasonally, ensure your cartridge filters are being stored correctly when out of season. Also, check them before the next season begins, as they can sometimes lose their quality over time even when not in use.

Pump filter systems should still run during the off-season every so often to keep the chemicals in the water ticking over. Therefore, you need to monitor your filters during the off-season. As with your pool as a whole, investing in a cover and properly closing your pool will also help keep your filters working efficiently.

A clean blue-tiled swimming pool

Choosing the Best Pool Filter


The filter is a crucial part of your swimming pool, so you need to get a quality unit. Making sure you choose a good swimming pool filter will save you a lot of money and effort long-term, so it’s worth getting advice from experts like our team at 1st Direct Pools.

Home Pool Filters

When it comes to home pool filters, they often fall into two categories:

  • - Side-Mount Filters
  • - Top-Mount Filters

Both of these are essentially the same thing, except the valves and other features are either on the top or side of the filter. Whether you need a top or side-mounted filter often comes down to how your pool is set up – it should be clear which will fit.

Many home filters will come with the same features, so the most important thing to note is the pressure. Ensure that the filter system you choose can cope with the force of your pool pump. Also, ensure that it’s a solid build as any cracks will cause a significant headache.

One outstanding option is the PerAqua Side Mount Filter. This model is as good as it gets when it comes to durable, expertly-designed swimming pool filters.

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Another model we highly recommend is the Tagelus Top Mount Filter. Again, this is a durable model designed for maximum reliability and easy maintenance, making it a great choice for owners with less pool experience.

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Commercial Pool Filters

Commercial swimming pools have additional requirements when it comes to pool filters. First of all, they are usually bigger and used more frequently, so the pressure is more intense. However, there are also issues like the time and regularity of use. The filter needs to be continuously maintained, much more so than with a home pool.

If you operate a small commercial swimming pool, we recommend the Lacron 24 Finaflow MBF. This model works with a running pressure of 2.5 bar and flow rate of 15m3/hr, and is also equipped with a handy sight glass, allowing for checks during operation.

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Filter Media

The vast majority of filters will require you to purchase the media separately, as this will need to be replaced more often than the actual mechanics.

Most filters that can work with sand media will also work with glass. If your filter uses a cartridge, you’ll need to continue using a cartridge.

Generally speaking, sand filter media is a good choice in most circumstances. However, if you’re willing to pay more, glass filter media is more effective at cleaning small particles and can last longer, so it’s often worth the investment.

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1st Direct Pools supply everything you need to keep an immaculate swimming pool. From swimming pool filters, sand and glass filter media, pool and hot tub chemicals and much more! We’re your one-stop-shop for all things swimming pools, so browse our collections or feel free to contact us with any questions or queries!

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