A successful start up begins with good training and a successful operation continues with good training. At Los Angeles Aqueduct Filtration Plant, training before and during operation was and is a continuous process. Planning the operation and maintenance is intensive activity. Getting the ozone/oxygen system online wasn't easy. Many problems surfaced as part of the initial operations. Some of those problems included: raw water to filtered water for cooling; fuses; oxygen filters; dewpoint probes; and ozone control valves. These problems were associated with the ozone portion of the system. This paper describes the oxygen/ozone system at LAAFP, including detailed descriptions of the oxygen and ozone processes, and other components. Pre-startup activities and training are described, as are startup problems and solutions. Major components of routine and nonroutine maintenance and training are described. Future changes to comply with CT values are discussed.