Why Reverse Osmosis? The process of Reverse Osmosis, whereby pressure is used to force water through a semi-permeable membrane that retains the solute, is a proven way to supply purified water to your aquarium and its inhabitants. The Aquatic Life RO Buddie 50 GPD is a highly affordable 3-stage Reverse Osmosis Unit that removes harmful substances such as heavy metal ions and Total Dissolved Solids (TDS) from your municipal water supply. Stage 1 - Sediment Cartridge - Incoming water first passes through a Sediment Cartridge, which removes particulate matter often found in tap water. Stage 2 - Carbon Cartridge - After particulates and debris are removed from the water, it then passes through a Carbon Cartridge where chlorine, chloramines, and other impurities are removed or neutralized. Stage 3 - RO Membrane - The final stage of purification occurs when water travels through the semipermeable thin film composite (TFC) membrane, removing any remaining solutes. The RO Buddie's compact size makes it ideal for placement in cabinets and other small spaces. It includes a handy mounting bracket for secure installation, while allowing convenient access to the unit's cartridges. The RO Buddie also features quick-release clips that make it easy to remove supply lines, and includes a canister cap wrench for easy replacement of the TFC membrane (accepts standard 11.75" membranes). It uses 1/4" flexible tubing with high pressure and temperature ratings for outstanding resistance to environmental stress cracking. A faucet adapter is also included for connection to standard male hose thread. For quality assurance and peace of mind, the RO Buddie is backed by a 1 year limited manufacturer's warranty. Please Note: 1/4" tubing to connect to water supply, filtered water and waste water connections sold separately.