distilled water will be far less conductive than water but not as good as de-ionised water. if the distilled water gives a similar reading to tap water it hasn't been distilled properly
how about we do this to get the max least conductive water, Get some bottled water that has been naturally filted ( the rock thing ) without any added vitamins or whatever, then we boil it then fill it up!
the point is more about preventing corrosion with in the water cooling system than its conductivity. a decent system that is well maintained should never leak.
And im the one who WON WOOOT!!!! lol (sorry but trifid insisted that it wouldnt conduct but i am electricity guy )
But no water is far better than air at cooling but then far more expensive and risky, as long as you are should 100000000% that your watertight move it into the case, otherwise you maybe looking at a new pc.
P.S. De-Ionized water IS non-conductive BUT as soon as an electric current e.g. mobo, is passed through it, it be comes normal (fairly clean) water. Plus all of the Anti algy, Corrosive agents will add electrons into the water.
See Trifid i do my reasearch, im just sad i didnt bet any money, the science teachers were alittle confused at the green water thou lol