I lived in an area where there was a lot of iron in the water. Stained toilets, tubs and sinks with yellow-bron stain. I used toilet cleaner. But rinse right after the stain is gone or it will take the finsh off. Do a small section at a time.
CLR works for lime, and Iron Out works for reddish iron deposits from well water.
CLR product in your hardware store should fix it.
This will clean the entire bathroom.
Heat up 1 cup of white vinegar, mix in about 1/4 cup of Dawn Premium. Not the dollar store kind, because it is too thin. When mixed, pour into a spray bottle and fill with water. Shake. Spray down the grout and let it sit overnight. In the morning rinse. If you have stubborn stains, spray again. Use this mixture a few times a week. It will keep your grout and tiles clean. Also works wonders in the toilet bowl to keep hard water stains at bay. Oh you only have to heat the vinegar one time when you add the Dawn.