Methods and apparatus for an improved contrast therapy device that delivers alternating heated and chilled temperature fluids to a contrast thermal therapy pad. Mitigation processes maintain water temperature in hot water tanks and cold water tanks in order to keep water temperatures in the respective tanks from drifting beyond a desired setpoint range when the system switches a therapy state from a cooling cycle to a heating cycle or from heating cycle to a cooling cycle. Thermal shock is reduced to the fluid tanks. Mitigation techniques include delaying actuation of a return path flow, such as via a diverting solenoid. Mitigating delay can be a static time delay based upon one or both of: a volume of water in a therapy pad and related volume and rate of flow; and meeting a threshold transition temperature for return fluid temperature.