When I was stationed in Fort Irwin, CA. The water was terrible it had tons of minerals. I have a Black Trans Am and if the water had the slightest chance to dry it left terrible spots/deposits. So I bought one of these:
http://www.autogeek.net/clinhofianda.html
Well we're about to move from our town house into a real home that has a well. So I was thinking of buying one of these just to use for filling the turtles tanks. My tanks are filled to the top anyways so those white lines aren't really an issue for me.
Thoughts?

