The Unique design of the 3-chemical chlorine dioxide generator mixes an acid, sodium hypochlorite and sodium chlorite to form a very high efficiency reaction to produce a high conversion ratio of aqueous chlorine dioxide solution. The proprietary eduction technique, along with precise dosing allows consistent and reliable production of chlorine dioxide solution within seconds. A water source is connected to the inlet of the generator, which is regulated and controlled by a solenoid valve. An ultrasonic level sensor measures the level of chlorine dioxide solution in the batch tank. When the level reaches the low level set point, it automatically opens the solenoid valve which allows water to flow into the system. A high efficiency eduction method mixes the three chemicals in a controlled sequence into the water. and rapidly produces aqueous chlorine dioxide solution.