When To Replace Your Pool Cartridge Filter

When to replace your pool filter cartridge?

If you own a pool, then you know that your filter system is the gateway to clean and sparkling water. It ensures proper circulation and prevents debris from building up in your pool. Which makes cleaning and maintaining your swimming pool much easier.

But even for the best filter systems, proper maintenance is still important (equally as important as servicing your pool heat pump). Especially when considering the pool cartridge filter.

You know, that fabric cylinder with (typically) blue plastic ends. It’s what stops all of those microscopic dirt and hair particles from getting back into your pool water. And it’s one of the most important parts of your pool filter system.

Yet unfortunately, cartridges don’t last forever. Sure, you can keep them going with some routine cleanings here and there, but even the best ones need to be replaced after some time. The question is when to replace your pool cartridge filter.

When to replace your pool cartridge filter | Lifespan

The answer to this question is highly dependent on the quality of the cartridge, how often it’s cleaned, and how much you use your pool. But to keep things simple, the average lifespan is about 2 years.  Granted, that’s not to say that lifespan can’t be longer (or shorter). Which leads into another question.

How do you know when your cartridge filter only needs a cleaning?

Rule of thumb

The bigger the cartridge, the longer the lifespan. And the more debris it can filter before it needs to be cleaned. So go for the biggest filter cartridges allowable for your pool.

When to clean your pool filter

Ideally, you should clean your cartridges every 2 months. That’s usually when you’ll notice dirt/debris buildup. But you don’t have to get too fancy with it. A simple rinse with the garden hose or filter flosser will do the trick.

But let’s revisit the lifespan question.

There are a few warning signs to look for when deciding when to replace your pool cartridge filter. If you notice a good portion of these signs, then your cartridges have probably reached the end of their life.

[Cleaning and replacing the cartridges still not doing the trick? It might be time to contact a pool repair service]

When to replace your pool cartridge filter | Warning signs

Water Pressure

The pressure of your pool’s filter system can tell you a lot about circulation/water flow.  For instance, when your filter’s pressure gauge reads 10-12 PSI above your clean reading, it’s likely indicating a blockage of some kind.

You’ll first want to check your skimmer and pump baskets. But if those are clean as a whistle, then your cartridges are likely the culprit. So if cleaning them doesn’t make a noticeable PSI difference, then the cartridges have reached their filtration capacity.

Over time with normal use, dirt and debris will embed itself into the cartridge fibers at a level too deep for cleaning to penetrate.

Coincidentally, this is also when the filters become much harder to clean, and still look dirty after multiple cleanings. But while we’re on the topic of cleaning….

Shorter cleaning cycles

A tell-tale sign of a filter replacement being needed is how often you have to clean it. When your cartridge filters are brand new, you’ll probably only need to clean them every 2 months or so.  But when you notice yourself having to clean them out nearly every month (or more often), then it’s time to replace them.

To piggyback onto the last point,  you should also pay attention to your PSI when cleaning. Make note of how long it initially takes your filter to reach it’s cleaning point (according to PSI). When the PSI starts shooting up rapidly despite multiple cartridge cleanings, then the filters are permanently clogged and no longer useable.

Water quality

Of course, the most obvious sign of a filter system issue is your water.

Sure, you keep your pool chemicals in balance, but how does the water look? Is it as clear as it was when you opened the pool?

If not, then a cleaning is definitely in order. And logically, if cleaning the cartridges doesn’t change the clarity of your water, well, you know what to do.

Cosmetic issues

Cosmetic issues, in some cases, can be a little misleading. Which is why we put them last. Because wear and tear is completely normal.

But how much is too much? Let’s take a look.

+Fuzzy/frayed fabric

Out of all the cosmetic defects to look for, this one is typically the most reliable in determining when to replace your pool cartridge filter. A brand new cartridge will have smooth, paper-white fabric. But an aged filter in need of replacement won’t look as pretty.

Replace your cartridge filter if you see:

• Holes in the fabric
• Frayed or fuzzy pleat edges
• Splits or cracks along the seams
• Flattened pleats

+Broken Bands

The bands that go around the edge of the filter help keep the pleats from flattening. But they can break easily, so they’re not considered a reliable indicator of when to replace your pool cartridge filter. Broken bands do, however, usually indicate aging. Especially when they break on their own. So in some cases, they can be considered early warning signs.

+Cracked Endcaps

Similar to the bands, cracked endcaps are more an indicator of aging. But it’s usually rough handling or harsh chemical exposure that will cause the endcaps to crack. In most cases, the endcaps on quality cartridge filters will outlast the lifespan of the filter’s fabric.

We hope this article helped you get a better idea of when to replace your pool cartridge filter. Although a fairly durable component of your pool system, your filter still needs proper maintenance. Making sure that your pool cartridge filters are in good shape will help keep your water clean and clear. But it’s not the only responsibility you have as a pool owner. Luckily, we have some powerful pool care tips that’ll make it easy to keep your pool in tip-top shape.