Have a Hayward EC-65 de filter. Found it quite annoying that I can't backwash the filter like some, and "bumping" the fitler isn't always effective, so I came up with a method to do some quickie backwashing and cut down the need to break open the filter. I cut in a "T" when an elbow used to be just downstream from the filter. Added a female DWV fitting to the open port of the "T". I use a DWV blockoff to close the port when backwashing isn't needed. To adapt a garden hose to do the
backwashing, I put together a male fitting to match the female fitting in the "T", a bushing to adapt the 1 1/2" pipe size down to a size that fits a garden hose adaptor, added the garden hose adaptor and an adapt to move the hose connector to a horizontal position. I also added a ball valve just downstream from this adaptor, to make sure the water from the hose gets to the filter and there you go, a quickie backwash adaptor for the Hayward EC series of DE filters.