Interesting ! Let us know what you come up with.
On a side there are certain rules I adhere to: no water near any electrical equipment that did not come that way by design (washer, dishwasher ok but no add-ons), no glasses of beer because the dog will find and drink it, no smoking in the house or car no matter what ! heheee...

dionb wrote on 2021-06-03, 21:18:

Hmm, yes, I can see how that would work. A bit worried about a copper block with my aluminium reserator though...

I watercooled my Pentium 4 with a copper NexXxos XP and a passive Innovatek Konvekt-O-Matic radiator. Used Innovatek Protect IP for corrosion inhibition. As advertised no corrosion occurred. Even added an aluminium cooler (AquagratiX 800, what a name!😄) for my X800 Pro some years llater because it was sold dirt cheap. No corrosion on that either.
With the right corrosion inhibitor there really doesn't seem to be an issue with mixing aluminium and copper. The bad experiences people had with mixing materials in their water loops is probably due to the old myth of destilled water being good against corrosion.