Hayward DEP 500 Series DEP85 85 SqFt Pleated Element DE Filter. The DEP 500 Series pleated element D.E. filters are Hayward’s first pool filters engineered with cartridge convenience and D.E. technology. These pool filters provide superior water clarity and make maintenance simpler and faster than ever. Trusted D.E. filtration offers greater dirt-trapping capabilities, while a reduced number of pleats significantly decreases cleaning time.