A pump system for a metal furnace , the pump system comprising: a tank comprising a tank chamber configured to receive a molten material; and a magnetic stirrer comprising a rotating permanent magnet , wherein the tank is positioned above magnetic stirrer and such that the magnetic stirrer is outside of the tank chamber , and wherein the magnetic stirrer is configured to generate a moving magnetic field in the molten material in the tank chamber to induce movement in the molten material, an inlet in fluid communication with the tank chamber and defining a flow path to the tank chamber for molten material entering the tank chamber ; and an outlet in fluid communication with the tank chamber and defining a flow path from the tank chamber for molten material exiting the tank chamber , wherein a transverse dimension of the tank chamber proximate to the inlet is different from the transverse dimension of the tank chamber proximate to the outlet, wherein the transverse dimension of the tank chamber is the dimension across a widest portion of the tank chamber , wherein a surface of the tank chamber comprises a non-linear curve between the inlet and the outlet , characterized in that the pump system further comprises a mixer , selectively positionable within and removable from the tank chamber, wherein the mixer comprises a body , and wherein the body comprises one or more fins along an edge of the body , wherein the mixer is movable between a lowered position and a raised position, wherein in the lowered position, the mixer is positioned at least partially within the tank chamber and/or at least partially within the molten material within the tank chamber , and, in the raised position, the mixer is positioned above the molten material within the tank chamber and/or outside of the tank chamber . a tank comprising a tank chamber configured to receive a molten material; and a magnetic stirrer comprising a rotating permanent magnet , wherein the tank is positioned above magnetic stirrer and such that the magnetic stirrer is outside of the tank chamber , and wherein the magnetic stirrer is configured to generate a moving magnetic field in the molten material in the tank chamber to induce movement in the molten material, an inlet in fluid communication with the tank chamber and defining a flow path to the tank chamber for molten material entering the tank chamber ; and an outlet in fluid communication with the tank chamber and defining a flow path from the tank chamber for molten material exiting the tank chamber , wherein a transverse dimension of the tank chamber proximate to the inlet is different from the transverse dimension of the tank chamber proximate to the outlet, wherein the transverse dimension of the tank chamber is the dimension across a widest portion of the tank chamber , wherein a surface of the tank chamber comprises a non-linear curve between the inlet and the outlet , characterized in that the pump system further comprises a mixer , selectively positionable within and removable from the tank chamber, wherein the mixer comprises a body , and wherein the body comprises one or more fins along an edge of the body , wherein the mixer is movable between a lowered position and a raised position, wherein in the lowered position, the mixer is positioned at least partially within the tank chamber and/or at least partially within the molten material within the tank chamber , and, in the raised position, the mixer is positioned above the molten material within the tank chamber and/or outside of the tank chamber . <EOS>