A mixing system for mixing fluids or the like in a mixing vessel. The mixing system includes a fixed conduit connected to the top portion of the vessel extends into the vessel. The system also has a rotating shaft 12 having disposed within the fixed conduit that rotates within the fixed conduit while the mixing system is in operation. An impeller 10 is attached to the rotating shaft 12. The impeller blade has a flat central disk portion 24, at least a pair of extensions 26 extending from a central disk portion, and at least two leading edges 30 defined by the outer periphery of the disk portion. Each leading edge 30 spans from one extension to an adjacent extension, and each leading edge 30 has at least a portion at which the radius of the leading edge from the center increases to form a continuous increasing radius curve. Each leading edge forms an increasing radius spiral edge surface in between the extensions.