I've been researching for a while on how to get the hardwater stains off of my white subway ceramic tiles. Many had advised to use vinegar but at the same time they say the vinegar will eat away at the grout. And I don't think vinegar would be a good choice for the silicone caulking around the tub? I have white subway tiles and white grout. I've tried Soft Scrub, CLR and Bar Keepers Friend. Soft Scrub will remove 80% with a ton of elbow grease but there's still some lingering stubborn stains.

The arrow pointing the piece of tile I cleaned with Soft Scrub that took 5 minutes of scrubbing for just one piece of tile. At this angle you can't see, but there are still some water stains on it.

Does anyone have any other recommendations that cleans faster and removes all the stains?