How Do You Know When It's Time to Change Your Pool Filter?

As a pool owner, your most important responsibility is to ensure proper pool maintenance, particularly for health reasons. Pools are vulnerable to contamination and need to be maintained carefully, so the most common question asked is how often do you change the filter?

Of course, you would want to change it when the filter looks dirty, but this is truly not the answer; ideally, there are earlier indicators to help you know when to change the filter before it reaches unsanitary levels. If not properly maintained, a pool can become the perfect breeding ground for bacteria and other microorganisms.

Top Three Indicators to Change Your Pool Filter

One way to maintain your pool filter cartridge is to change it according to the manufacturer's suggested schedule. Most filters have a lifespan of anywhere from six months to two years, but this varies depending on factors such as the size of your pool and how often it's used.

Your water chemistry is also an important factor in determining when it's time for a new filter because chlorine levels can affect both the lifespan and effectiveness of your current pool filter cartridge. If you're not sure when it is time for a new pool filter, then here are some signs that will help guide you when making this decision:

1) The Flow Rate Slows Down Significantly After Running Through the Pump

If you notice that the water is no longer flowing as freely as it used to, then this could be an indication that your pool filter needs to be replaced. When the filter becomes too clogged with debris, not only does the flow rate slow down but the pump can also start making strange noises.

Watch the Water

You may be able to see water flowing back into the pool after leaving the pool. This is a clear sign that something needs to be done and changing your pool filter should be at the top of your list.

It's also important to monitor how long it takes for the pool to fill up after running the pump - if it's significantly slower than before, then there may be a problem with your pool filtration system.

2) There Are Particles That Stick to the Sides of Your Pool

If you start seeing large particles sticking to the sides of your pool, this is an indication that the filter is no longer able to keep up with the amount of debris in the water.

Notice Where Particles Accumulate

You may also notice debris or dirt collecting in front of your skimmer basket.

This could be due to a number of reasons such as a clogged filter or a dirty cartridge, so it's important to troubleshoot and determine the cause.

3) Your Pool Water Is Cloudy

Cloudy pool water can be caused by a number of factors, but it's usually an indication that there are too many contaminants in the pool and your filter needs to be replaced or serviced. You may also notice debris floating around in the pool when you look at it from above; this just means that the filter is no longer able to trap the dirt and debris.

Green Patches

On the other hand, if you start seeing green patches or slime forming on the pool surface, this is a clear indication of algae growth. Some people think that if they see algae, it is time to change their filter - however, this is actually because there is not enough chlorine in the water to combat the algae growth. Algae thrive in environments with low chlorine levels, so if left unchecked it can quickly take over your pool and become difficult to get rid of.


If you're seeing any of these signs, it's likely time to change your filter. It's best to replace your filter before it becomes completely clogged and causes damage to your pump or pool liner. Most filters should last anywhere from six months to two years, but this can vary depending on the factors mentioned above. Be sure to monitor pool usage and water chemistry to determine when it's time for a new pool filter.

The LifeSupplyUSA store has an excellent selection of replacement pool/spa filters that are very inexpensive. These filters are manufactured to high-quality control standards and will last just as long as the OEM filter. You can shop & save here on pool filters trusted by professionals. 

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