If you have a sand pool filter, backwashing is an important part of your swimming pool maintenance routine. Regular backwashing will help to maintain water clarity and preserve your pool equipment. So whether you are new to the pool care game, or you have been doing it for years, we have some helpful hints that will make the process super quick and simple.

What is Backwashing?

Backwashing a sand filter is the process by which dirt and debris that build up in the sand are rinsed from the filter media. During this process, the flow of water through the filter system is reversed so that contaminants are flushed out of the sand. The dirty water is then expelled through a waste line or drain. Note that DE filters (diatomaceous earth filters) also require regular backwashing, while cartridge filters must be manually cleaned instead. 

When to Backwash Your Sand Filter

If you are unsure how to tell when your filter needs to be backwashed, there is a simple rule to follow. Any time the pressure gauge on your filter reads 8-10 psi (pounds per square inch) above normal, it’s time to backwash. Backwashing is also recommended after heavy rains and after treating an algae bloom.

Steps to Backwash a Sand Filter

Follow this easy step-by-step process to backwash your sand filter:

  1. Shut off the pool pump.
  2. If you have a backwash hose, make sure it is securely connected to the backwash valve.
  3. Turn the multiport valve handle to the ‘backwash’ position.
  4. Turn on the pool pump and let it run for 2-3 minutes, until the water runs clear through the sight glass. 
  5. Turn off the pump.
  6. Switch the filter valve handle to the “rinse” setting.
  7. Turn the pool pump back on and let it run for about one minute, or until the water flowing through the sight glass is clear again.
  8. Turn the pump off again and switch the valve handle back to the normal “filter” position.
  9. Switch the pump back on and make sure the filter pressure has returned to its normal level.

More Helpful Hints for Backwashing a Sand Filter

  • To greatly improve your pool water quality and filtration, use a  sand filter cleaner before backwashing, at least a few times a year.
  • Be aware of where your discharge water is flowing during the backwashing process. Some pool owners like to use the water to irrigate plants or lawns, while others route it into the home’s sanitary sewer cleanout. Check state and local regulations to find out what is permitted in your area.
  • Backwashing too often can actually reduce the effectiveness of your sand filter, so never backwash if the pressure gauge reads less than 5 psi above normal. 
    To avoid wasting pool water, avoid backwashing for longer than necessary.

Sand pool filters are a popular choice for pool owners because they are affordable and very easy to maintain. As you can see, it is easy to DIY your regular sand filter maintenance so that your pool water stays clean and clear. If you have any questions about how to backwash your pool filter, or about any of our pool products, please give us a call today at 800-574-7665 or visit us online at doheny.com. Our friendly and knowledgeable experts are here to help.