Is a good question? Although I am not sure from your question where the fan headers are for.."ill use the fan headers to control for instance the radiator fans?"
It appears you are trying to use one PA2 ultra to control 2 pumps?? yes
The 3 pin fan header on the D5 is "tacho" signal for connection to motherboard for RPM reporting, so bios does not report cpu fan fail and refuse to boot. It is not a fan power source.
Second 3 pin is for a flow meter.
The 4 pin fan header on the D5 is "bus" and also not a power source.

With the first pump connected to the "power output" of the PA2, the PA2 will control the pump (Aquabus 1 connected to AQ5) I would imagine that you can connect the second pump via aquabus and the built in single channel controller in the D5(pump 2) does the control. So with d5 connected to PA2 aquarbus 2....there will be no free interfaces.


Aquaero5 is a independent controller, you can use all 4 channels (ie fan control) regardless of what is connected via aquabus.

Connecting a D5 USB to a PA2 appears to be duplication, both have built USB interfaced controllers.

Quoted from "afa7336"

I am looking to setup a dual loop with the D5 Aquacomputer USB Aquabus pumps. If I chain the Poweradjust 2 Ultra to the Aquaero 5 XT (That I know how to do), on the two free Aquabus interfaces that are on the Poweradjust 2 Ultra can I install the pump Aquabus cable and still use the fan headers to control for instance the radiator fans?

The Poweradjust has two Aquabus ports and can be daisy chained together, but MPS devices only have one so they need to be used with splitter cables. Not sure what you mean by two free aquabus on the poweradjust 2 ultra? ... one is input / one is output to the next device.

So you would have the aquabus high port on the AQ5 connected to the fist aquabus port on the poweradjust, then the second aquabus port to a splitter cable that connects to both of the aquabus ports on the two D5 USB's