You may want to look a little closer around the ports. The
MANUAL states:
3.5. Integration into the cooling loop
Connect the return line to the reservoir connector engraved with the word “IN”
and connect the other line to the remaining connector. Use light force only when
screwing in fittings in order not to damage the threads in the plastic base part!
Edit: I believe you can see the 'IN' marking below the right port, looking at the ports (
ultitube.jpg)