[Richard]

sorry, I have been absent for a couple of days. The resin systems I was referring to are more technically known as Ion exchange beds. They are used to make deionized water which mean completely void of minerals. The beds are usually used in tandem, one for positive ion and one for negative ion exchange. Used all the time to make purified water in the medical manufacturing industry. The ion depleted water attacks metal, even stainless. My high school chemistry teacher is going to cringe at this explanation, but the ion depleted water is really trying to replace the ions or minerals to restore it's electrolytic balance. It sets up electrolytic corrosion in metals trying to find electrons. Similar in some respects to galvanic corrosion but doest require two dissimiliar metals.

As stated earlier, you do not want to drink deionized water, because it will leach the minerals out of your body.

So, you say what is the difference between distilled, RO, and DeI water. Distilled removes almost all minerals but does not leave any residual molecular electrical charges in the water. Works because only the water boils leaving the other stuff behind. RO, reverse osmosis, passes water through a membrane(filter) that is too small to pass the minerals. DeI uses an ion exchange bed to electrically remover the minerals from the water.

As you can guess, there are hybrid systems that use both RO and Ion Resin beds. I am sorry that caused some confusion in what I was saying was safe to drink and not safe to drink.