Ozone Spring deionized water system is an arrangement of DI tanks and other components that are used to produce high purity water. The DI tanks are typically made of fiberglass and come in various sizes to accommodate different feed flow rates. A deionized water system can be as simple as a one tank setup or as complex as a multi-tank system with supporting equipment such as reverse osmosis, ultraviolet (UV) disinfection and elaborate water quality monitoring equipment. DI tanks contain ion exchange resin which selectively remove ions from water.