I have a Hayward Perflex EC65 DE filter and there is a constant leak/fast drip coming from the drain plug area. I've switched out 2 brand new drain shutoff valves (Hayward 2-Way Ball Valve Replacement Fitting - 1-1/2 Inch - SP0723 | Ace Pools) and it still leaks. I improvised and installed a cap to seal the drain however when I remove to backwash, there is a fair amount of water/DE in the pipe and cap.

Any thoughts on what is causing this leak? Is there a barrier between the drain plug and filter that may be damaged causing the DE to also leak out?

Thank you in advance!