A mixer, comprising: a housing comprising a fluid inlet, an additive inlet, and an outlet, the housing defining a mixing chamber in fluid communication with the fluid inlet, the additive inlet, and the outlet; an impeller disposed in the mixing chamber, wherein, when rotated, the impeller draws fluid through the fluid inlet; a slinger (134, 200) disposed in the mixing chamber and configured to receive the fluid from the impeller and to receive an additive from the additive inlet, wherein, when rotated, the slinger (134, 200) slings the fluid and the additive radially outwards and wherein the impeller and the slinger (134, 200) form a slinger/impeller assembly; a stator (120, 300, 400) disposed at least partially around the slinger (134, 200), the stator (120, 300, 400) comprising vanes (156, 308) spaced circumferentially apart so as to define flowpaths (158, 310) therebetween; the slinger (134, 200) and the impeller have inlet faces (134-1, 136-1) and backs (134-2, 136-2) respectively, and wherein the slinger (134, 200) and the impeller are disposed in a back-to-back configuration, such that the impeller drives the fluid radially outward of the slinger (134, 200), upward in the mixing chamber, and then radially inward toward a middle of the slinger (134, 200); characterized in that the stator forms a shearing ring disposed radially around the impeller/slinger assembly, the stator comprising first and second annular portions (146, 148) stacked together, the first annular portion (146, 302) defining a first flowpath area (158, 310) and the second annular portion (148, 304) defining a second flowpath area (158, 310), wherein the first flowpath area (158, 310) is greater than the second flowpath area (158, 310) and wherein the second annular portion (148, 304) is disposed between the first annular portion (146, 302) and the impeller. a housing comprising a fluid inlet, an additive inlet, and an outlet, the housing defining a mixing chamber in fluid communication with the fluid inlet, the additive inlet, and the outlet; an impeller disposed in the mixing chamber, wherein, when rotated, the impeller draws fluid through the fluid inlet; a slinger (134, 200) disposed in the mixing chamber and configured to receive the fluid from the impeller and to receive an additive from the additive inlet, wherein, when rotated, the slinger (134, 200) slings the fluid and the additive radially outwards and wherein the impeller and the slinger (134, 200) form a slinger/impeller assembly; a stator (120, 300, 400) disposed at least partially around the slinger (134, 200), the stator (120, 300, 400) comprising vanes (156, 308) spaced circumferentially apart so as to define flowpaths (158, 310) therebetween; the slinger (134, 200) and the impeller have inlet faces (134-1, 136-1) and backs (134-2, 136-2) respectively, and wherein the slinger (134, 200) and the impeller are disposed in a back-to-back configuration, such that the impeller drives the fluid radially outward of the slinger (134, 200), upward in the mixing chamber, and then radially inward toward a middle of the slinger (134, 200); characterized in that the stator forms a shearing ring disposed radially around the impeller/slinger assembly, the stator comprising first and second annular portions (146, 148) stacked together, the first annular portion (146, 302) defining a first flowpath area (158, 310) and the second annular portion (148, 304) defining a second flowpath area (158, 310), wherein the first flowpath area (158, 310) is greater than the second flowpath area (158, 310) and wherein the second annular portion (148, 304) is disposed between the first annular portion (146, 302) and the impeller.