Hydro Logic Pre-Evolution High Capacity Pre-Filter for the Evolution-RO (HL31027)Ensure your Evolution RO1000 runs more efficiently. Helps protect the RO membranes and extends their life. Less filter changes and maintenance every 7,500 gallons of purified water. Cleanable sediment filter is re usable. Combination of KDF85 and the KDF55 with eco friendly catalytic carbon filter reduces chlorine, chloramines, iron, sulfur, and heavy metals. great for city or well water. Highly recommended when using more than 150 gallons of purified