When you’re enjoying a crystal clear pool, all you’re thinking about is the water. I can guarantee no one is thinking about pool filter care. As long as the water is clear and the temperature feels good, what else is there to think of

The reality is, there are so many parts, pieces, and efforts that go into maintaining a beautiful pool. Aside from the water – chemicals and clearing visible debris – there are all the parts that go into pool maintenance.

Most pool owners understand that the filter is a key component of keeping the pool clean. However, they may not realize that they also need to clean the filter periodically. Keeping your filter clean ensures the filter performs at its best and keeps your water clear.

To help you stay on top of your pool filter care, we’ve compiled some of the most common questions. And we even added some helpful tips and tricks!

Pool Filter Care 101: Five Common FAQs

Pool filter care can be confusing. We chased down 5 of the most commonly asked questions – and answered them!

1. How often do pool filters need to be cleaned?

Typically, cartridge filters need to be cleaned every six weeks. During the height of pool season, you may want to at least check your filter more frequently. During the winter, when your pool sits empty, you can probably push it to 10 weeks between cleanings.

However, these time frames may vary based on the surrounding environment. For example, if your yard features heavy tree cover, more frequent cleaning may be required, even in the winter.  On average, a pool filter cartridge’s pressure reading should display between 8 – 15 PSI.

2. How many hours a day should I run my pool filter?

You should run your pool pump an average of 8 hours a day to properly circulate and clean your water. Residential pool water only needs to be turned over once daily to have proper filtration. However, you don’t have to run your pool pump consecutively. For example, you can choose to run it for three hours in the morning before you leave for work. Once you’re home in the later afternoon, just turn it on for another 5 hours! 

3. Is it better to run a pool filter at night or day?

It’s always best to run a pool filter during the hottest times of the day. That’s because the sun causes chlorine depletion in your pool. Thus, if you run your pump at night, the sun has all day to attack the chlorine in your pool. That can cause algae to bloom fast, leading to bigger issues. However, due to energy costs or other reasons may not want to run your pump for 8 hours midday. In that case, aim for at least 3 hours in the day. Then just split the other hours in the morning and evening or night.

4. Can I leave the pool filter on for 24 hours?

You can, but it’s unnecessary and might spike your energy bill! Although it’s generally recommended that all the pool water undergo filtration every 24 hours, the pump does not need to run all the time. 8 hours of filtration during a 24 hour period is sufficient.

5. How do I know when my pool filter needs cleaning?

Pool filter cartridges need to be cleaned when the pressure gauge rises 8 PSI above normal operating pressure. Remember, a pool filter cartridge’s pressure reading should typically display between 8 – 15 PSI.

Additionally, when the timeframe between pressure increases begins to shorten significantly, the filter cartridge probably needs to be replaced.

Pool Filter Care: How to Clean Different Types of Filters

Cartridge

To clean a cartridge filter, turn the pump off first. If the filter is below the water level of the pool, there should be valves that have to be closed to prevent the pool from draining when the filter is opened. Make sure those are closed before proceeding.

Open the air bleed valve on the top of the filter and the drain port on the bottom of the filter. This will allow the water to drain out. Then open the body of the filter. This may involve unscrewing some knobs, removing a nut at the top, or removing a bracket. Remove the cart or carts. Make sure you note their position and orientation so you have no trouble reassembling the unit!

Rinse out the filter tank and take the carts to where you want to clean them. All you need is a garden hose with a nozzle. Wash the carts from the top to the bottom aiming 45 degrees down at them.

Always remember to wash both the outside portion and the inner portion. In fact, it’s a good idea to start at an identifying point on the cart and wash all the way around. Then you will repeat on the inside. Once finished, reassemble the filter, close the drain port, and open any valves you closed. Then turn the pump back on. When water runs steadily out of the air bleed valve, close it and you’re all set. If the pressure after cleaning does not return to your standard starting pressure, you will need to do a more thorough cleaning. At that point (if you haven’t already realized!) it’s best to call a pro to service your filter.

Sand

Sand filters will have either a push/pull main valve or a multiple position valve (multiport). When changing the position on the main valve, you MUST turn the pump off first. Next, make sure that any valve on the discharge/waste line is open. Make sure you’ve attached the discharge hose is and rolled it out to where you want the dirty water to go.

After turning off the pump, move the lever to the “BACKWASH” position and restart the pump. Most multiports have a view glass so that you can see the debris coming out of the filter. Other filters will have a section of transparent pipe on the backwash line. The water will run clear for a moment, then get dirty, and finally run clear again. When the water in the glass is clear, turn off the pump. If you have a multiport valve with a “RINSE” setting, switch to that. Otherwise, switch to “FILTER” and run the pump for about 15 seconds.

Repeat the backwash cycle. Finally, reposition the valve back to the normal “FILTER” position, and you’re all set.

Take note that this process removes water from the pool. Thus, be sure to keep an eye on the water level and don’t start the cleaning process if the water is already low.

DE

DE filters come in 2 varieties. The first type makes use of a push/pull or multiport valve for the cleaning. With this kind of DE filter, the cleaning procedure is exactly the same as cleaning a sand filter (see above). The only difference is that much of the DE is removed along with the dirt. Therefore, you have to add more after cleaning the filter.

Because the backwashing doesn’t remove all of the DE, only add 80% of what the filter calls for. Once in a while, it is necessary to open up a DE filter and do a much more through cleaning. In that case, it may be best to call in a pro.

The other kind of DE filter utilizes a handle to shift the internal assembly up and down. This knocks the DE and dirt off of the filter and down to the bottom. It is known as a “bump filter”. To clean a bump DE filter, turn off the pump and open the air valve on the top for about 5 seconds. Close it again, then slowly push the handle down and quickly raise it up 5 times. Restart the pump and check to see that the psi dropped more than 2 psi. If it did, you’re all set and you don’t need to add any new DE to the filter.

If it didn’t drop enough, repeat the bumping procedure. Remove the plug from the bottom of the filter and run the pump another 30 seconds. Replace the plug, open the air valve on top and run the pump until water is coming out of the air valve. Do this whole process twice and you’ll be all set to add 80% of what the filter calls for, just like the other type of DE filter. And like the other type, once in a while it will be necessary to do a much more thorough cleaning.

The Bottom Line on Pool Filter Care

In summary, pool filter care is a necessary chore. It should be tended to about every six weeks, and the specific steps depend on the filter type. If that seems like a lot of work or a lot of details to keep track of, call in the pros. That way you can be guaranteed that your filter will be in top shape, working at full capacity to keep your pool water clear. The pros at The Pool Butler are happy to help! Reach out today to get started.