These could also be a possible option for (howtogetridofstuff.com/stain-removal/how-to-get-rid-of-hard-water-stains). Just follow the simple steps.
1. Fill the basin as high as you can with water.
2. For sinks, add 1 cup of vinegar. Tubs, 1 liter. Toilets, 1 cup.
3. Let the solution soak in the basin overnight.
4. Drain and rinse.
5. For extra-stubborn stains, make a paste from baking soda and white vinegar and scrub. Continue nightly soaks until they’re gone.
Be aware that not all hard water stains can be removed. Mineral deposits can be dissolved, but sometimes the metals in the water bond with surfaces (most commonly glass) and leave permanent white stains.
Hope this helps!
