A Venturi pump chlorine dioxide generation device with one or more special ninety-degree bends with half-spherical mixing stations including: at least one ninety-degree bend with two half-spherical mixing stations between the sodium hypochlorite introduction point and the acid source introduction point, at least two ninety-degree bends with two half-spherical mixing stations between the acid source point and the sodium chlorite introduction point, and at least two ninety-degree bends with two half-spherical mixing stations between the sodium chlorite introduction point and the vacuum chamber of the Venturi pump. Each ninety-degree bend with two half-spherical mixing stations is an elbow section of cylindrical conduit or pipe wherein the two outer segments of the ninety-degree bend each have a spherical shaped expansion area to create a half-spherical concave section inside the conduit or pipe.