Quote Originally Posted by Michael R 1974 View Post
...regarding steam distilled being better than deionized for XTOL, actually I recall Gerald Koch saying it could potentially be the other way around if the steam distilling apparatus introduces Iron into the water...
It's difficult to imagine that the cold side of a distillation process (condensing steam) might introduce more iron into resulting water than a deionizing plant would. In either case, iron levels have to be orders of magnitude lower than what comes out of some taps.

I've never had an XTOL failure either. Steam distilled water is sold here in grocery stores at $3 for a 2-1/2 gallon container. Compared to the cost of everything else in photography, that's noise level. I see no reason not to keep using it for mixing/diluting XTOL and other powdered developers, diluting liquid developer/fixer concentrates and mixing Photo-Flo rinse solutions. Ultra-cheap insurance, especially where film is concerned.