Try this.....It has worked great for me. I have very hard well water and i use it regularly after the white staining starts to build up a little. I apply it to the dry surface and let it sit for about 5 minutes. Then rub with a plastic scrubbie and it all comes off.

Bio Clean: Eco Friendly Hard Water Stain Remover (20oz Large)- Our Professional Cleaner Removes Tuff Water Stains From Shower doors, Windshields, Windows, Chrome, Tiles, Toilets, Granite, steel e.t.c https://www.amazon.com/dp/B01M7T3D99/ref=cm_sw_r_cp_api_i_i8SCCbT26A9E9

I (and others) have recommended this product. It is fabulous for removing hard water stains from tile, glass, metal, plastic, etc. I'd tried everything until I found this. My window washer discovered it, too and uses it on my windows.

There are other products with the same name..be sure it is this one. I first got a sample at Ace Hardware...you could see if they have it if there is an Ace near you. It looks like you might be able to get a free 1 oz sample from their website. Also sold/available on Amazon. I've only used the cream in tubs shown here, so I can't vouch for the lotion in the bottles.

https://www.bio-cleanproducts.com/

Try white vinegar & water, 50/50 mix, spray the areas and let it stay for a couple minutes, don't let it dry, and just rinse off. I always have a spray bottle of the mix in the bathroom and kitchen for cleaning, also works awesome on windows.

Robin,

I agree with Christine, if your gray tile is not natural stone, I'd try a mix of vinegar, water, and dawn soap. If possible warm-up the vinegar in the microwave. Apply Bar Keepers Friend cleanser and scrub the area.

We use this method a lot at our clients house (but keeping in mind vinegar cannot be used on many of the surfaces in a typical home. For example, you should never use vinegar on stone surfaces like granite, marble, limestone, onyx or travertine because it will dull the surface).

Let us know what method worded for you!