Question:
Deionizing is much cheaper and simpler than distilling. For manyapplications you don't need distilled purity, just removal of the ioniccontaminants.

To remove any inadvertent dissolved contaminants downline from the still. I would say the DI is a post-treatment of distilling, yielding DDI.

This sounds like the "distilled water is poison to drink" myths. Maybe youcould explain your theory in chemical terms.

Answer: Perhaps you are confused about reverse osmosis, distillation andionic demineralization with cation and anion specific resins. All ofthese produce the same product, pure water. No chemical difference withthe possible exception of a few dissolved gasses that will pass throughthe membrane filter in the RO unit.

I have lived in the middle east (Bahrain and Dubai) where the source ofdrinking water is reverse osmosis producing deionized water. No onedies from it. No one gets sick from it. They just quench their thirst.I have lived in the tropics where the surface water was essentially rainwater, less than 5 parts per million total hardness. No one dies, noone gets sick. People have drank it for centuries. I have lived inareas where the source of drinking water was collected rain. Totalmineral content less than 1 part per million. No one dies from drinkingit.

I currently have a reverse osmosis unit that produces our drinkingwater, it tastes better than the tap water. I have not died and myteeth have not fallen out.

For the record I have a major in chemistry and have made my living as achemist. I also know uninformed bull when I see it.