EK, from EK's own latest research, said in the end it was any uninhibited distilled water causing the problem (ie lack of corrosion inhibitors) and they showed their nickel plating would not hold up under just pure distilled water over time...testing here:
http://www.ekwb.com/shop/EK-IMAGES/EK_STAINING_TEST.pdf
And that goes along with fact that many that used just distilled water alone, even some that used inhibited fluid, had damaged EK nickel plating.
Plating companies that use nickel for anticorrosion protection, such as in marine use, use 75 micron thick nickel plating, tedious prepping, and outer phosphate or chrome hardening and its way more expensive than what we pay for. Minimum recommended is 15-20 microns with hardening. I think swiftech uses such hardening.
Suggest 4 micron thick plating which EK states they use, and their mass prepping probably used to keep it affordable, and you would get laughed at... if you called that anti-corrosion coating.
EK wants you to use anticorrosives (which is not compatible with PT nuke and many other additives) to slow the inevitable loss of 4 microns plating, to hopefully a point where you will upgrade before gets to bad.
plain distilled vs distilled with silver vs distilled with pt nuke, in a couple months all is going to be ion soup from picking up copper, zinc (if brass rad) etc ions from rad/blocks....so doubt it matters whether you pre-polute the water with copper ions via pt nuke or not, other than few weeks head start your create.
