I'm really at a loss here. I regularly clay, wash and wax my car. I use hardwax every few months and for every wash in between, I use some type of spray wax/quick detailer. My paint feels like glass. I don't get how the calcium in this water could penetrate the paint.
1999 Techno Violet Metallic BMW M3
2005 Audi B6 S4 quattro 6MT
2004 BMW 330i
1986 BMW 535i