I wouldn't run a watercooling pump via PWM. I would set to the RPM you want (preferably 100%) and let it run. For liquid cooling, there isn't much real benefit to allowing your pump to cycle up and down based on CPU temps.
- temps can change very rapidly and altering a pump's RPM up and down and up and down isn't going to net you cooling benefits since coolant and water needs to absorb a very large quantity of heat (in watts) in order to rise a single degree, which changing pump RPM is not likely going to impact
- running a pump at full speed (or constant speed) means you have ONE variable to contend with if you need to evaluate temperatures, rather than pump RPM and radiator fan RPM.
A lot of people are enamored by this idea of needing to micro-manage cooling and lighting and temps and this and that, but when it comes to liquid cooling pumps, the best performance comes at 100% pump speed, no matter what the fan speed on the radiators. Pumps are not noisy, if they are, then something is very wrong, Pump noise should a very quiet hum and really no more - even at 100% operation.
I sit within 2 feet of my D5 pump at 100% and there's absolutely no way to hear it over the actual radiator fans.
My recommendation would be to only set your radiator fans with PWM curve - set the pump at full speed.
It's a DDC, that's what it's meant for.