Abstract: A method and apparatus for improving the performance of a pump uses a pump performance disk kit comprising an impeller disk having a plurality of impeller disk blades extending at angles from a planar surface of the impeller disk such that when the impeller disk is attached on top of an impeller of a pump the total number of blades for use by the pump, and thus the performance, is increased. Interior edges of the impeller disk blades are located such as to prevent rotation of the impeller disk and lock the impeller disk blades in a location approximately halfway between blades of the impeller of the pump. An anticavitation disk is also attached on top of the impeller disk to eliminate the cavitation caused by coolant spilling out the open face of the pump impeller by blocking off the open spaces between the blades.