What is the best way to remove hardwater stains from a shower

For the tiles make a mixture of white vinegar,water,a dab of dish soap and a dab of jet dry.Ally heavily and leave on over night.See if this broke up the water marks.You can also try Mr.Clean Magic Eraser.Once you get the residue down ,on a daily basis use a daily shower spray,a squeeze,etc.

You could also try removing them with a paste made from baking soda and vinegar. Smear the paste over the surface of the stains and let set for 15 minutes. After the mixture settles in, scrub clean and rinse with clean warm water. Its important that you wipe dry right after using the shower because you don't want water setting on the newly cleaned surface

I use Bar Keepers Friend but I'm not sure if it is safe for your black tile.

I used Oxiclean mixed with hot water in a spray bottle for my floor tiles & it worked amazing. Then scrub with a stiff brush. If you don't use Oxiclean maybe a friend or family member can give you some to try so you don't waste your money if it doesn't work. Really did work wonders on my floor tile & grout though. Good luck!

thank you for the suggestion..I will give it a try!

If it’s cultured marble tile, we will clean it using Benaz that removes all the hard water stains, mold, soap scum and etching. If it’s ceramic, porcelain or natural stone tile, we will use Imperia that soaks into the tile to eliminate the damages. Once we clean, we will seal the tile with a clear topical solvent based sealer and will offer you a 5 year labor warranty. For more info, visit : https://goo.gl/4HVrn1 .