Periodically you have to clean the debris and contaminants out of your Hayward DE Filter. This process can be done at three levels: 1- by backwashing the filter; 2- by extracting and cleaning the grid assembly; or 3- by extracting and cleaning each grid in the assembly. For more information on Backwashing, see our guide on "How To Backwash a Hayward DE Filter". For a more thorough cleaning, you can extract and clean the grid assembly. This guide discusses the procedure for this second level of cleaning the grid assembly. For the most thorough cleaning, you can pull the Grid Assembly and take it apart to wash down each Grid individually. This third level of cleaning is generally done once a year at the end of the season. For more information, see our guide on "How To Remove and Clean Hayward DE Filter Grids".