1st stage: high-capacity 10" inline polypropylene sediment depth filter will effectively remove dirt, sand and sediment from the water. Recommend changing every 6-8 months. 2nd stage: high capacity 10" inline coconut shell carbon filter to remove chlorine, tastes, odors, cloudiness and colors. Recommend changing every 6-8 months. For over 20 years, APEC has been an industry leading manufacturer who specializes in high performance ro systems. As the original manufacturer, we have dedicated a knowledgeable and sincere team that is committed to providing customer SATISFACTION in hopes to bring many years of enjoyment and good health for you and your family.