Three tank integrated (mixing tank, mixing tank and storage tank) continuous brewing, easy to operate and use; The single water inflow and dosage can be adjusted arbitrarily, and the reagent preparation concentration can be changed with the process requirements. Microcomputer is used to accurately control the single water inflow and dosage, and the concentration deviation of the prepared reagent is less than 5% of the set value; The ultrasonic liquid level detector is used to detect the liquid level, with high sensitivity, the reaction is not affected by the conductivity of the solution, and the concentration of flocculation preparation is not limited. The whole machine is made of stainless steel, with high mechanical strength, no deformation and long service life.