The tightness of the tanks is guaranteed by the 2,2 mm thick geomembrane. Membrane is sodium chloride resistant and holds a PZH certificate. That is, it can be used wherever groceries appear. Paint which is inside of the tank painted holds the PZH certificate also. Paint protects the tank against the corrosion additionally. Due to geomembrane water has no contact with the steel walls of the tank. The 60mm thick polystyrene isolation ensures a suitable temperature of the liquid.