A method and apparatus are provided for controlling the operation of a pump, such as a centrifugal pump, featuring steps of either adjusting the operation of the pump, or issues a warning to a user of the pump of an undesirable operating condition, or both, based on a comparison of an actual torque value and a corrected torque value either alone or in combination with a further step of compensating the corrected torque value based on a mechanical power offset correction. The corrected torque value may include a Best Efficiency Point (BEP) torque value and may also be compensated for based on at least the current operating speed of the pump. The pump has a controller for performing the steps of the method. The controller can compensate the corrected torque value based on the square of the speed change of the pump. The comparison may include a ratio of the actual torque value to the corrected torque value.