We are now stocking the Pentair GRO-2550 system includes the new high performance Green RO encapsulated membrane, providing high quality reverse osmosis water while wasting 3 times less water to the drain compared to a standard membrane. The pre-filter reduces particles to prolong the life of the RO membrane. The RO membrane separates water molecules from dissolved salts and minerals. The RO filtered water is sent to the storage tank until you need it. When you turn on the drinking water faucet, the filtered water from the storage tank is sent through a carbon polishing filter which provides final taste and odor filtration before the water reaches your glass. Cleaner, fresher water whenever you want it!