I checked the 2 gallons of distilled water in my garage. I purchased them awhile back for battery top-offs. Printed on the label of one of them is: "Micron Filtered and Ozonated". Stamped on the other one is simply: "Best if used by 03/20/05" (I recall buying it in the fall of 2003.) They are two different manufacturers/bottlers. So it seems that there may be variation in the purification procedure after all. Is "ozonation" what you were referring to as UV treatment? If so then that is the type I'll look to buy.

Regards, Vince