Been using the Waterwise 880 distillation water purifier for about 5 months now and it is without a doubt one of the better purchases I have made concerning health. The unit holds one gallon of water and will make at least 4 gallons of pure great tasting(No chemical or any other bad taste tap water can can impart)pure water. It is a counter top model which we use for coffee, tea, cooking or drinking. I usually make a couple gallons a day and have to clean the cooker after each use. The cleaning process gives a visual example of what we are putting in our bodies each time I clean to fill. I can see nothing I feel I'm missing as rscotty mentions, what is left after each cooking is about a teaspoon of brown liquid which looks something like tea, a chalky powder dry on the sides, and a corrosion type residue in the bottom where the heating coils are.
I bought the recommended cleaner and a 6 pack of charcoal filters(I am still on the original one). I only use the chemical cleaner after about 10 gallons which brings the stainless steel boiler back to pristine condition, I usually use a none abrasive pad to scrub out as much of the residue as I can. It makes little difference whether I use plain tap water or the filtered ice maker/drinking water spigot, the nasty looking results are the same. However I did use some natural spring water "Crystal Springs" which we offer in our waiting room and the residue was markedly less and had none of the brownish solution in the bottom. Next I want to experiment with a gallon of distilled water offered in supermarkets in the area, I have a feeling this test may reveal something interesting.
Bottom line is my Waterwise Distiller works great and is worth the investment, the only drawback I feel is I won't drink the water out in resturants(icky), therefore may not be getting all the water my system needs. I do take vitamins so I'm not lacking for anything I may get out of the water from the Barren River that Bowling Green, Ky uses for its water source! Biff