This disclosure relates to a multi-PID controller system where a variable such as the temperature of a fluid in a reservoir is stabilized using two or more PID controllers to optimize the control of an actuator, such as a flow control valve of a refrigeration system, to control a flow rate. The system also allows for the optimization of the PID control of a fan speed based on the optimized regulation of the control valve and a comparison with other input variables. The setpoint temperature is further stabilized by setting up in proximity of the desired setpoint a deadband analysis to prevent overlap of the PID-driven heat regulation and the multi-PID-driven cold regulation.