Hi Nicola, in my opinion you should not do this (because Ekwb has provided their Coolstream radiators with copper lines and not nickel-plated copper. Ek cryofuel's fluids are also optimised for this purpose, so I would leave other manufacturers alone. If the liquid tips over, you won't have much fun with your chosen colour and there will certainly be deposits in the radiator. To be on the safe side, I also use EK radiators from the Coolstraem range.