How to Clean a Pool Filter: Sand, Cartridge and DE
A dirty filter is behind more cloudy water and high pressure readings than almost anything else. Here is how to clean yours properly.
Clean your pool filter when the pressure gauge reads about 8 to 10 PSI above its normal clean reading. Sand filters are cleaned by backwashing. Cartridge filters are removed and hosed off. DE filters are backwashed and then recharged with fresh DE powder, with a full teardown once or twice a year. In Georgia, expect to clean more often during spring pollen, summer swim season and fall leaf season.
How to tell when your filter needs cleaning
Your filter's pressure gauge is the best guide. Note the reading right after a thorough cleaning. That is your clean pressure. When the gauge climbs about 8 to 10 PSI above that number, the filter is loaded with debris and needs cleaning. Other signs include weak return flow, cloudy water that will not clear, or a cleaner that slows down.
The three filter types at a glance
| Filter type | How it is cleaned | Good to know |
|---|---|---|
| Sand | Backwash, then rinse | Simple to maintain; sand needs replacing every several years |
| Cartridge | Remove and hose off, deep clean periodically | No backwashing, uses less water; cartridges need replacing over time |
| DE (diatomaceous earth) | Backwash, then add fresh DE; full teardown periodically | Finest filtration; needs the most upkeep |
Safety first. Always turn the pump off before working on your filter. Open the air relief valve to release pressure before opening the filter tank or removing the lid. Never open a filter that is still under pressure, and follow your filter's manual for your specific model.
How to clean a sand filter
- Turn off the pump.
- Set the multiport valve to Backwash.
- Turn the pump on and run until the water in the sight glass or waste line runs clear, usually a couple of minutes.
- Turn off the pump and set the valve to Rinse.
- Run the pump on Rinse for about 30 seconds to resettle the sand.
- Turn off the pump, set the valve back to Filter and turn the pump back on.
Always turn the pump off before changing the valve position.
How to clean a cartridge filter
- Turn off the pump and open the air relief valve.
- Remove the filter lid and lift out the cartridge or cartridges.
- Hose each cartridge off from top to bottom, working between the pleats. Avoid a pressure washer, which can damage the fabric.
- Check for tears, flattened pleats or crumbling end caps. Damaged cartridges should be replaced.
- Every so often, deep clean cartridges with a cartridge cleaner to remove oils and buildup that a hose cannot.
- Reinstall, close the lid securely, turn the pump on and bleed out the air.
Many owners keep a spare set of cartridges so one set can dry and be cleaned while the other is in use.
Need help with your filter or not sure which type you have? Stop by our Alpharetta store at 2900 Holcomb Bridge Rd with your filter's model number and we will point you in the right direction.
How to clean a DE filter
- Backwash the filter following the same steps as a sand filter.
- After backwashing, add fresh DE powder through the skimmer with the pump running. Use the amount listed on your filter's label.
- Once or twice a year, do a full teardown: remove the grids, hose them off thoroughly and inspect them for tears before reassembling.
Never add DE to a sand or cartridge filter. Check local rules for disposing of DE backwash water.
How often to clean your filter in Georgia
There is no fixed schedule. Go by the pressure gauge. That said, expect to clean more often during spring pollen season, busy summer swim weeks, after storms and during fall when leaves are dropping. In winter, with less use and cooler water, cleaning is usually needed less often.
A clean filter fixes a lot
If your water is cloudy, your pump is struggling or your cleaner is slowing down, a dirty filter is often the cause. Read our guides to cloudy pool water and pool pump troubleshooting.
Frequently asked questions
Filter questions?
Pool Supply Atlanta helps pool owners across Alpharetta, Roswell, Milton, Johns Creek and Sandy Springs. Visit us at 2900 Holcomb Bridge Rd, Alpharetta, GA 30022 (Mon to Fri 9am to 5pm, Sat 9am to 4pm) or call 678-691-6124.
Lost your filter manual? Find it in our equipment manuals and parts diagrams guide.
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