Soak a clean cloth in hard water remover solution. Choose a hard water remover that will not damage the type of floors in your bathroom. Be especially careful, if you have natural stone tiles, as these can get damaged by some hard water remover products.
Lay the cloth over the stains on the tile floor. Let it sit for at least an hour. This will give the solution time to loosen the stain.
Remove the cloth and scrub away the stain with a soft-bristled scrub brush.
Re-soak the cloth and lay it back over the stain. Cover the cloth with plastic wrap to prevent it from drying out and let it sit there overnight.
Remove the plastic wrap and cloth and scrape the tile with a paint scraper. Work until the stains are gone.
Mix 1 cup of salt with 1 cup of baking soda. Both will help serve as a light abrasive to scrub away the stain on the tile.
Add 1 cup of vinegar to the solution and mix it until the solution is thick and smooth.
Spread the paste directly onto the stain and let it sit for several hours until it is completely dry. The solution will naturally bubble for several minutes. This is the reaction between the alkaline baking soda and the acidic white vinegar, which will help loosen the stain.
Rinse the area with a sponge soaked in water then dry it off completely with a rag.