A system and apparatus for controlling the delivery of fluid from a reservoir, in relation to the ground speed of the vehicle delivering the fluid. Including a system where a hydraulic pump and motor are the components to drive the delivery of the fluid from the reservoir. The hydraulic motor is controlled to vary the output of the fluid pump based on a programmable logic controller (PLC) program. Where an operator selects the desired density of fluid to be pumped, the PLC controls fluid pump flow by controlling the hydraulic motor speed based on the vehicle ground speed.