How to Clean a Pool Filter (DE, Sand and Cartridge)
No matter how often you use your pool, if it is open, eventually the pool filter will need to be cleaned. You will know it's time to clean the filter when the pool water turns cloudy, the filter pressure is elevated from when the pool was opened, or the return water pressure has decreased.
You should clean a pool filter every few weeks or, at a minimum, monthly depending on your exact pool setup and location. Fortunately this is an easy maintenance item for any pool owner to do and generally does not take longer than an hour at most.
Here's how to clean your pool filter, with instructions for cartridge, sand, and DE filters.
What Type of Pool Filter Do You Have?
The first step to cleaning your pool filter is to identify what type you have. This can be done by simply looking at the shape of filter and the type of piping going into your filter. There are three main types of pool filters:
- Cartridge filter: Cartridge filters are usually used on smaller above-ground pools and tend to be on the smaller side. The filter itself is usually secured by a large nut at the top that has to be removed to gain access to the filter inside. The filter will look like a large cylindrical air filter. Most of the time this type of filter does not have a multiport or similar type valve to control water direction.
- Sand filter: A sand filter is the most common type of pool filter. It is usually filled with sand or another filter material. They are potbelly-shaped, and the filter housing is made of plastic. This is controlled by a multiport on top or in front of the filter.
- D.E. filter: DE filters are cylindrical in shape and usually have a stainless steel or metal body. This type of filter has screens inside that catch D.E. powder to enhance the filtering effect. You will have to periodically add D.E. powder via skimmer mouth to maintain efficiency.
How Often Should You Clean Your Pool Filter?
No matter what type of pool filter you have, you should clean or backwash your filter at least once a month. However, some pools may need to be cleaned more often based on what type of filter it has and how many leaves and how much debris falls into the pool.
Being mindful of what the internal filter pressure will help you understand how hard your filter has to work to maintain a clean pool. For example, cartridge filters will have their pressure rise the fastest and should be cleaned every other week because they will lose efficiency permanently if they remain dirty for too long. This is part of the reason they are mostly used for smaller above ground pools and not larger commercial or residential pools. The lower the pressure the system has to operate, the easier it will be for your pool to stay clean, which will help extend the life of your pool system.
When cleaning any filter type there is a high probability that water will squirt out somewhere and debris might fly in an uncontrolled manor. Always wear safety glasses and be mindful of your surroundings. Thoroughly inspect all your piping before starting this procedure and make sure that there are no blockages in your piping and all valves are open to avoid a dangerous pressure build up.
What You'll Need
Equipment / Tools
For Cartridge Filters
For DE & Sand Filters
- Scoop for DE powder
For Sand/DE Filter Types
- 1 DE powder
Remove the Cartridge
Take the valve off the filter then open the filter top and remove the cartridge.
Hose Off the Cartridge
Hose down the cartridge's outside filter housing, making sure to get in between all the filter flaps on both directions. It is helpful to do this once in one direction and then flip the cartridge over 180 degrees (upside down) and repeat. This will help get any stubborn algae or debris off of the filter and increase its service life.
Reassemble the Filter and Run
Reassemble the filter, then open the valves and bleed system with bleed valve on the top of filter. The system will be fully bled (i.e., all the air will be out of it) once water comes out of bleed valve.
Sand and DE Filter
Check Water Level
Before you begin, verify water is ¾ up skimmer mouth. This is to account for the water loss you will have during the backwash process.
Prepare to Backwash
Turn off the system and move the multiport to the backwash setting. Open backwash/separation tank valve, if present. Roll out backwash hose, if present, to a drain area you are sure won't be flooded by the water.
Run the Pump
Turn the pump on and observe the sight glass. When the sight glass turns clear, turn the pump off.
Rinse and Filter
Move the multiport to “Rinse” and turn the pump on for three seconds, then shut it off. Next, move the multiport to “Filter.” Close the backwash/separation tank valve, if present.
Restart the Pump
Turn the pump on and let it run. If you have a sand filter, this is the last step to cleaning your pool filter.
Add DE Powder (for DE Filter)
Once the filter is still running, add 2 to 3 scoops of D.E. powder to the skimmer closet to the filter system.
What household item can I use to clean my pool filter?
A hose and water works best to clean a pool filter. It is generally not a good idea to use any other chemicals or cleaning supplies because they can wear away the various filter materials and shorten the service life of your pool filter plus wreak havoc with the pool chemistry.
How often should you clean your pool filter?
How do you clean algae out of a pool filter cartridge?
If your cartridge has algae on it you would clean it the same way as any normal debris, using a high pressure hose or nozzle. Make sure you get in between each flap and hole on the cartridge and clean in different directions. After as much algae is removed as possible, reassemble and add an algaecide to your pool to treat the pool as a hole and to eliminate whatever algae residue is left behind. Note that algae stains, so even if you get all the algae off the filter, if it was there for a while or was allowed to dry on the cartridge, it will always have a stain. The stain however, should not affect its ability to maintain a clean pool.