"Wes" wrote in message
...
"Tim" wrote:

IIRC,
our machines had to use deionized water.

I heard a horror story where a facility put in a reverse osmosis system to
take all
impurites out of the feed water. Then they started having even more
problems. Really
pure water attacks the alloying elements in the plumbing.

It may have been taking out the iimpurities, or it may have been a pH effect
from the process. Some kinds of "distilled" water are slightly acid.

So is rainwater. I understand that the latter is the result of picking up
carbon dioxide from the atmosphere on the way down, and forming a very weak
solution of carbonic acid. But I got that second-hand.

--
Ed Huntress