Apparatus comprising: a signal processor or processing module configured at least to: receive signaling containing information about system energy consumption related to multiple pump combinations running in a multiple pump system; and determine whether to stage or de-stage a pump (12a, 12b, 12c, 12d) in the multiple pump system, based at least partly on the signaling received, and wherein the signal processor or processing module is configured with control logic or a control logic algorithm that utilizes calculated flow data that is mathematically determined from various pump and motor parameters, including speed, torque, and power or from calibrated flow curves stored in an evaluation device, wherin the signal processor or processing module is further configured to implement control logic or a control logic algorithm based at least partly on the system energy consumption taking the form of system specific energy that is a measure of energy used per unit mass for the multiple pump combinations running in the multiple pump system, and wherein the signal processor or processing module is configured to determine the specific energy of current pumps running and an effect on a total system specific energy of adding another pump (12a. 12b, 12c, 12d) to meet process demands related to the multiple pump system, the signal processor or processing module is configured to make a comparison between two calculated values of system specific energy; and to choose a pump combination either having a lesser value for staging, or having a greater value for de-staging; Characterized in that: the signal processor or processing module is configured to evaluate and not consider for selection any pump (12a. 12b, 12c, 12d) in a pump combination having a power value which exceeds a nameplate motor rating multiplied by a pre-selected service factor and/or a flow value which exceeds a predetermined BEP Limit Ratio; and the signal processor or processing module is configured to stage automatically an additional pump (12a. 12b, 12c, 12d) if either cases occurs prior to calculating the system specific energy. receive signaling containing information about system energy consumption related to multiple pump combinations running in a multiple pump system; and determine whether to stage or de-stage a pump (12a, 12b, 12c, 12d) in the multiple pump system, based at least partly on the signaling received, and wherein the signal processor or processing module is configured with control logic or a control logic algorithm that utilizes calculated flow data that is mathematically determined from various pump and motor parameters, including speed, torque, and power or from calibrated flow curves stored in an evaluation device, wherin the signal processor or processing module is further configured to implement control logic or a control logic algorithm based at least partly on the system energy consumption taking the form of system specific energy that is a measure of energy used per unit mass for the multiple pump combinations running in the multiple pump system, and wherein the signal processor or processing module is configured to determine the specific energy of current pumps running and an effect on a total system specific energy of adding another pump (12a. 12b, 12c, 12d) to meet process demands related to the multiple pump system, the signal processor or processing module is configured to make a comparison between two calculated values of system specific energy; and to choose a pump combination either having a lesser value for staging, or having a greater value for de-staging; Characterized in that: the signal processor or processing module is configured to evaluate and not consider for selection any pump (12a. 12b, 12c, 12d) in a pump combination having a power value which exceeds a nameplate motor rating multiplied by a pre-selected service factor and/or a flow value which exceeds a predetermined BEP Limit Ratio; and the signal processor or processing module is configured to stage automatically an additional pump (12a. 12b, 12c, 12d) if either cases occurs prior to calculating the system specific energy.