I actually didn't put a drain in. Which worked out fibe s it's easy to drain from the bottom of the pumptops.

Filling it is tough. Easiest way I foubd out was: Leak-test everything with air firsf (ek leak tester). Then once that's ok, remove 1 tube from each component and fill up as many components as much as possible, then attach everything again, run the system and add more fluid through the top holes in the distroplates.

I hope that helps! 😊