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How to Clean a Hayward EC40 DE Filter

By Cellina LaForey
Clean Hayward pool filters for maximum performance.
Swimming pool and pool house image by Jim Mills from Fotolia.com

If you own a Hayward EC40 DE filter, you’ll quickly understand the importance of having a clean filter ready for next year’s pool use. On occasion, it may be necessary to perform a thorough filter cleaning midyear. While the process is not difficult, it can be messy. The length of time it takes depends on the age of your filter. Older 12-bolt models require a little more time than the newer ones.

Backwash the Hayward EC40 DE filter. Unplug the pump. Disconnect all sources of electricity. Place the face cover over the skimmer. Although this step is not absolutely necessary, it helps to make the process less messy.

Disconnect the hoses from the filter. Remove the skimmer hose from the filter. If you have placed the face cover over the skimmer outlet, you shouldn’t get drenched with a rush of water. Remove the return hose from the filter. The return hose transfers filtered, clean water back to the pool. If your pool is equipped with a bottom drain, disconnect it. If you don’t have a plug to prevent the water from pouring out of the bottom drain, place the disconnected end of the hose into the pool to prevent a huge, wet mess.

Open the runoff spout (normally used for backwashing) and allow the water to drain. Open the air valve to speed the draining process.

Take the top off of the filter housing. Newer filters have a convenient ring to loosen that will enable you to remove the top of the housing. For older models, you need to loosen and remove the 12 bolts at the top of the housing to lift the top off.

Wash the filter fingers. Hayward EC40 DE filters have filtration fingers that become dirty over a season of use. Set your garden hose nozzle on the most powerful stream and power wash each of the fingers.

Soak the filter fingers overnight in a 5-gallon bucket of diluted muriatic acid (read the instructions on the container for proper dilution). This step is recommended for the end-of-the-year cleaning and on occasion midyear if you've had a particularly busy and dirty pool.

Rinse the muriatic acid thoroughly from the fingers. Once you’re done, the fingers should appear white.

Replace the filter top, reconnect the pool hoses, plug in the pump and add the DE.


Things You Will Need

  • Water hose
  • Muriatic acid
  • 5 gallon bucket


  • Clean the filter either early in the morning or late in the day to avoid standing in the hot midday sun. It's especially important to time it right if you have the older 12-bolt model.

About the Author


After spending over 20 years writing for businesses in both the insurance and technology industries, Cellina LaForey now spends her time as a freelance writer. The time she spent working with Fortune 100 companies has provided the experience necessary to easily transition into full-time writing.