Quote Originally Posted by mookien View Post
If by "purified" you mean "filtered", then that is insufficient to eliminate minerals in the water that may cause discoloration on/of the wool. If that is the case, try "distilled" water which does not contain any minerals. But, in any case, good luck.
It's a common misconception that distilled water is better than ordinary water. You are correct that distilled H2O does not contain minerals but because of that distilled water acts like an acid when in contact with metals. It will leach minerals out of the metal. I would never use distilled water in any iron as it will shorten the life of the iron. In fact, Rowenta issues a warning against using distilled water in their irons.

Ordinary bottled water low in calcium, manganese, iron, etc. is best.