Keeping marble shower clean
Six months ago, we remodeled our master bath. Our shower is white marble which I clean daily with mild dishwasher liquid soap, and weekly with a granite & natural stone cleaner. It's clean and very attractive. A few weeks ago I noticed yellow staining at the bottom of the shower. It does not appear to respond to my cleaning. I am puzzled as to what is causing this and why my natural stone cleaner is not removing it. I should add that we have been careful to only use ph neutral products in the shower. Any thoughts and suggestions?