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How To Clean And Backwash A Cartridge Pool Filter (Correctly)

How To Clean And Backwash A Cartridge Pool Filter (Correctly)

No one likes cleaning. But as a responsible pool owner, if you want to keep your pool looking it’s finest, you’ll need to put in the work.

Thankfully, besides chlorine (or a similar sanitizer), swimming pools come equipped with a filter that does a lot of the heavy lifting for you. 

One such water purifier is a cartridge filter, which absorbs impurities the sanitizer has destroyed. Having a clean cartridge filter saves you from swimming in a dirty, cloudy pool.

Let’s talk about how you can keep it clean for the duration of its life.

Why Clean Your Cartridge Filter?

Pool owners have their pick between a sand filter, cartridge filter, and DE (diatomaceous earth) filter, each one having their pros and cons.

As your pool’s sanitizer (be it chlorine, bromine, or salt) kills off bacteria, viruses, and general debris in the water, the pool system cycles the water through the cartridge filter. This is where the debris ultimately ends up, keeping the pool water clean.

Pools are turned over a minimum of once a day, taking roughly 8 hours. With water cycling that much, it affects the filter’s performance in the long run. The only way to keep it working effectively is to clean it out.

The upside of cartridge filters is that their cylindrical, pleated design also makes them easy to clean, but the downside is you’ll need to remove them from the filter tank and hose them down.

Both sand and DE filters allow you to clean them through backwashing, whereas this is not possible when using cartridges. While backwashing seems more convenient, it takes a bit more time compared to quickly hosing off, or even replacing a cartridge.

Under normal use, you can get anywhere from 3 to 5 years of life from a cartridge. They also can reduce your energy costs due to their ability to filter with low pump pressure. With slower water flow, the longevity of the filter will be increased.

How To Clean Your Cartridge Filter

Cleaning your cartridge filter should be done once every 2 to 6 weeks. This depends on how much use the pool gets and how much debris the filter is exposed to. 

The filter tank’s pressure gauge should be monitored so that you know when to clean the cartridge. When it rises 8 to 10 PSI over it’s starting point, you’ll know it’s time to clean the filter.

Additionally, once a year, you’ll need to subject the filter to a deep cleaning.

What you’ll need before starting:

  • A garden hose with nozzle attachment
  • Cartridge filter cleaning solution
  • A 5 gallon bucket
  • Spray lubricant
  • A replacement O ring (backup)
  • A replacement filter cartridge (backup)

Step 1. Turn Off Your Pool Pump

First up, turn off your pool pump. This will keep water from entering the filter tank while you’re performing maintenance on it.

Step 2. Remove The Filter

Open up your cartridge filter tank and remove the filter. Inspect it for any damage. If it’s damaged you’ll need to replace it.

Step 3. Hose Down The Cartridge

While the cartridge can obviously stand up to water flow, you want to ensure that you don’ t damage it while you’re cleaning. This can happen if you’re using a pressure washer to blast the debris off. 

The nozzle you’ll want to use for this is either a standard garden hose spray nozzle, or a dedicated cartridge cleaning tool that hooks up to your hose. The cylindrical cartridge is designed with pleats in it, and the cartridge cleaning tool can get in between them a little easier than if you were to use a spray nozzle.

Cartridges stand upright in the tank and water passes through them. It’s important that you spray them at a downward angle. This will ensure the debris gets pushed down the length of the cartridge, and not pushed through it. 

If you push debris through it, it will end up back in your pool once you return the cartridge to the tank and run the system.

Step 4. Inspect The Cartridge

It’s unreasonable to expect the cartridge will still look brand new after weeks of use. 

After hosing it down, inspect it again to make sure you’ve removed all the debris from it.

If not, use a cartridge filter cleaning solution for some extra elbow grease. You should only need to spray it down, and let it soak for a few minutes before rinsing.

Step 5. Put It Back Together

With the cartridge now clean, you can put it back into the filter tank. You’ll want to inspect the tank’s O-ring next, to ensure it’s still in good shape and capable of preventing leaks.

If it’s still in good shape, add some lubricant to it and reseal the tank. If it‘s damaged in any way, replace the O-ring.

Step 6. Fire It Up

Now that the cartridge is reset, the O-ring inspected, and the tank resealed, you can turn the pool pump back on and run your system.

Don’t forget to check the tank’s PSI reading, making sure it has dropped 8 to 10 PSI, back to it’s “normal” range.

Yearly Deep Clean

Once a year the cartridge should be deep cleaned, as months of use will cause debris buildup that a simple hosing down may not remove.

Deep cleaning requires you to soak the filter in a diluted solution of cartridge cleaner. Do this overnight, and rinse it off in the morning.

The Pressure’s On!

A clean cartridge filter translates to clean pool water.

Keeping on top of your maintenance routine is imperative to keep your pool safe for swimming. 

As long as you monitor it’s pressure gauge, you should have no problems when it comes to the performance of this filter.

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