If all a pool filter did was clean dead bugs and hair out of your pool, it would still be an amazing invention. But a pool filter does a lot more than that, so keeping it clean is crucial for a healthy pool.

Today I’ll be breaking down the types of pool filters and showing you how to clean them, so you can have the sparkling, clear water you deserve. 

Why Clean a Pool Filter?

The pool filter is crucial for keeping a pool clean and healthy. Whatever kind of filter system you have, it removes larger particles like dirt, hair, and insects from the pool water, as well as finer particles like bacteria and other contaminants. A pool filter traps and holds all those particles, keeping them out of the water. 

As part of the pumping system, the filter also plays a role in the even distribution of chemicals in pool water, so that your pool water is healthier and more consistent. 

Of course, since your pool filter ends up holding all that dirt and debris, you have to clean it regularly, to get those contaminants not just trapped, but out of your pool altogether. Without regular cleaning, the water filter in your pool will clog just like the air filter on a vacuum cleaner, and simply not work as well. 

Types of Pool Filters

How and when you clean a pool filter depends on what kind of pool filter you have. There are three main types of filter:

Sand Pool Filter

As you may have guessed, with a sand filter, the water is filtered through a canister of fine sand. The sand traps dirt and debris, and can filter out particles as small as 20 microns in size. 

Cartridge pool filter

Pool cartridge filters have a pleated design that looks a lot like the air filter in a car. Water flows from the outside to the inside of the filter, trapping particles as small as 5 microns along the way. 

Diatomaceous Earth Pool Filter

Usually called DE pool filters, diatomaceous earth is a porous powder, that comes in a canister a bit like a sand filter. The filter has a fabric manifold, that gets coated in the DE powder. DE has microscopic openings, and can filter out particles as small as 3 microns. 

How Often Should a Pool Filter be Cleaned? 

Sand and DE pool filters have two levels of “cleaning”. They can be backwashed, which simply flushes debris out of the filter and removes clogging so they can operate normally, or they can be cleaned, which means removing the filter and manually cleaning it.

Backwashing simply means running the pool pump in reverse for a short time, and is recommended for a quick flush of these two types of filters. 

As a general rule, filters should be cleaned in approximately these time frames: 

  • Sand pool filters should be backwashed every 1-4 weeks, and cleaned once a year. 
  • Cartridge pool filters should be cleaned every 2-6 weeks, with a deep cleaning once a year. 
  • DE pool filters should be backwashed every 1-3 months, and dismantled and deep cleaned twice a year. 

While regular cleaning and maintenance scheduling depends on the kind of pool filter you have, there are some clear signs that a pool filter needs to be cleaned, no matter what type you have. The reason is because, for all pool filters, as they fill up, they become clogged. 

You should always check your filter if the back pressure in your filter system rises, or if your circulation flow rate decreases. So if you notice an increase of 5-10 psi in pressure, or if your circulation drops, it’s probably time to clean the filter. 

You will also want to check the filter if you notice pool water that is cloudy or tinted in color. 

How to Clean aNY TYPE OF Pool Filter 

Here are the easiest ways to clean a pool filter, no matter what kind of pool filter you have. Be sure to read and follow the manufacturer’s instructions, because specific brands may vary a bit. 

How to Clean a Sand Pool Filter

For regular cleaning of a sand pool filter, all you need to do is backwash the system. However, once a year or so, you do need to clean the sand. 

To clean a sand pool filter, you will need: 

  • A sand filter cleaner

Follow These Steps to Clean a Sand Pool Filter:

  1. Backwash the filter for 3-5 minutes
  2. Turn off your pool pump and set it to “filter”
  3. Open the pump lid, and pour sand filter cleaner into the strainer basket. Follow the manufacturer’s instructions for the correct quantity of cleaner. 
  4. Turn your pool pump on for 10-15 seconds to carry the cleaner into the sand filter itself
  5. Turn off the pool pump and leave it off for at least 8 hours (or more, depending on the size of your pool). 
  6. Backwash the filter for 3-5 minutes to remove any debris dislodged by the cleaner
  7. Turn your filter system back on to function normally
  8. Check the PSI in your system, to ensure the filter is working properly

How to Clean a Cartridge Pool Filter

To clean a cartridge pool filter, you will need: 

  • A garden hose with a spray nozzle

You also may need: 

  • A cartridge filter cleaning solution
  • A five gallon bucket
  • Spray lubricant
  • A replacement O ring (in severe cases)
  • A replacement filter cartridge (in severe cases)

Follow these steps to clean a cartridge pool filter: 

  1. Turn off the pool pump and filter, and slowly release air from the system.
  2. Following the manufacturer’s instructions, open your pool filter and remove the cartridge
  3. Inspect the cartridge for damage. You may need to replace the cartridge if it has been damaged. 
  4. Use the spray nozzle on your garden hose to clean the cartridge, rinsing between all the pleats. Don’t be too harsh with the water pressure, or you can damage the surface and render the filter less effective. 
  5. While your filter doesn’t need to be pure white, check it to see how clean you have gotten it with water. If it looks fairly clean and free of particles, you may be done.
    1. If your filter still looks dirty after spraying it clean, use a commercial filter cleaner that is recommended by the manufacturer. 
    2. If your filter still looks dirty after cleaning it with a product, you may need to use a bucket to soak the filter overnight in a dilution of your filter cleaning product. 
  6. When the filter is clean, check the O ring on the bottom to make sure it isn’t damaged. If it is damaged, you may need to replace it. If it isn’t damaged, apply a small amount of lubricant to help preserve the O ring. 
  7. Rinse the cartridge and the O ring
  8. Replace the cartridge in the filter, and turn the pool filtration system back on. 
  9. Check the PSI to make sure that your filter system is operating properly. 

How to Clean a DE Pool Filter

Before you begin, it’s good to know that diatomaceous earth is abrasive on the skin and respiratory system, and should not be touched with your bare hands, or breathed in powder form. And, from time to time, you may need to clean a DE filter with muriatic acid. Be sure to use proper protection when handling hazardous materials. 

Like a sand filter, you can perform routine cleaning of a DE pool filter by simply backwashing the system. However, you will need to periodically remove and clean the filter more thoroughly. 

To clean a DE pool filter, you will need: 

  • A garden hose with a spray nozzle
  • Diatomaceous earth powder
  • Spray lubricant
  • Gloves. If you are working with just DE, gardening or household gloves are fine. If you are working with muriatic acid, you will need chemical resistant gloves
  • A face mask. If working with just DE, then you can use a medical mask that covers the nose and mouth. If you are using muriatic acid to clean the filter, you may need a respirator. 

You also may need: 

  • A DE filter cleaning product
  • A five gallon bucket
  • A muriatic acid solution
  • If working with muriatic acid, you will need safety goggles
  • A replacement O ring (in severe cases)
  • A replacement manifold or filter grid (in severe cases)

Follow these steps to clean a DE pool filter: 

  1. Backwash the system for 3-5 minutes
  2. Turn the pump off, and remove air from the system
  3. Open the drain plug and let water drain from the filter
  4. Open the filter tank and remove the manifold
  5. Using a garden hose, rinse out the tank itself
  6. Using a garden hose with a spray nozzle, rinse off the manifold and filter grids and clear way all debris
  7. Inspect the manifold and filter grids to make sure they are intact and not damaged 
    1. If the manifold or grids are still dirty after spraying them clean, you may need to use a commercial DE pool filter cleaning product. Follow the manufacturer’s instructions. 
    2. If the manifold or grids are still dirty after using a commercial cleaner, you may need to soak them in a five gallon bucket in a muriatic acid solution overnight
  8. Inspect the O ring inside the tank to make sure it is intact. If it is damaged, you may need to replace it. If it isn’t damaged, apply a lubricant to protect it
  9. When they are clean, replace the manifold and grids inside the tank
  10. Create a slurry of DE and water, following your filter manufacturer’s instructions to determine the correct amount. 
  11. Turn on the pool pump and release air from the system
  12. Pour the slurry into the pool skimmer within 60 seconds of turning the system back on

Conclusion

Following these steps will help you keep your pool filter clean, no matter what type of filter you have. Regular cleaning helps your filter system last longer, work better, and keeps your pool water balanced and healthy.