I’ve had almost convinced myself on marble etching and all as i love a slab of local BC canada marble. ( i’ll post it). but i kind of forgot i had hard water and the thing that works great with hard water is vinegar and other acids CLR etc. which is a forbidden with marble. i’m
think cleaning the fixtures / sink which one does periodically to avoid deposits.

so i’m guessing it’s a problem. ?? any experience. ??