Since the earliest days of Avista Technologies, we recognized that our ability to impart useful product information and product use guidelines to our customers was essential to our success. Our goal in writing the Essential Users Guide is to provide concise answers to the most frequently asked questions regarding Avista products as well as providing troubleshooting and operational guides for RO and its auxiliary processes such as granular media filtration. The guide also contains use instructions for the Avista Advisor, software designed to select and dose Vitec scale inhibitors and Roclean® cleaners. Avista wrote the essential Users Guide for RO system operators, designers and students, covering both theory and practice.