The fundamental design of this cooler system is that the PUMP mounted on the CPU chip should always run at full speed. In your case, that means plugging it into the PUMP_FAN header and configuring that for a PWM Mode control and default full speed. In fact, the wiring of the pump makes use of a quirk of the design of 4-pin fans. When you plug a 3-pin fan into a 4-pin header using the new PWM Mode of control, that fan will always run full speed. So the PUMP in this system is wired like a 3-pin fan, and has a female connector on it with THREE holes. Then the RAD FAN speed will be controlled automatically if you plug that into your CPU_FAN header. That header uses as its guide the temp sensor inside the CPU chip, and it will govern the RAD FAN speed according to that internal temperature. Having ONLY the fan speed change, and NOT the pump speed too, means those two do NOT "fight each other" to maintain control.