Starter model with automatic measurement and control of the pH value. A properly controlled pH value is pre-condition for an efficient and effective water care. It protects the technical equipment of the swimming pool from corrosion, independent of the particular fresh water quality. The integrated dosing equipment is cost-efficient and space saving. Durable dosing pumps with almost wear-free stepper motor, optimal adjustment to requirement within a range of 0.3 - 3l/h dosing capacity, reduction of operating costs. Dosing is possible up to a maximum counter-pressure of 1.5 bar.