APEC Water Essence UV + Alkaline 75 GPD 7-stage complete filter set is made with high quality filtration components to prolong the lifespan of your reverse osmosis system. Compatible with APEC Water ROES-PHUV75 with serial number AZ-PHUV-3000 and above. 1st Stage: sediment filter - removes dust, particles, and rust, extending the life of the membrane and system.2nd and 3rd Stage: carbon block filter - gets rid of unpleasant chlorine, tastes, odors, cloudiness and colors, also removes VOC and other common chemicals from the water.4th Stage: high rejection 75 GPD TFC reverse osmosis membrane - removes a wide variety of contaminants including arsenic, bacteria, chlorine, lead, fluoride, chromium, radium and more.5th Stage: continuous UV sanitization - destroys up to 99.99% of bacteria, viruses and cysts.6th Stage: coconut shell refining carbon filter - removes any possible residual taste from the tank.7th Stage: pH+ alkaline re-mineralizing calcium filter - adds high purity calcium carbonate to increase water alkalinity. For over 20 years, APEC Water Systems has been an industry leading manufacturer who specializes in high performance RO systems.