Acid is the shortcut. But you have to be careful.

You can remove calcium scale from tile with a mild acid cleaner, but go slow and test first.

That white crust is mineral buildup from hard water or imbalanced pool chemistry. Muriatic acid (diluted 10:1 with water) works fast. Apply with a sponge or spray bottle, let it sit a minute, scrub with a soft brush, rinse. Do not let it dry on the tile or it etches the finish.

For stubborn spots, a pumice stone works well on wet tile. Keep the stone wet, rub gently. It wears down the scale without scratching the glazed surface. Never use dry — that’s how you put scratches in your tile.

Commercial calcium removers exist. They’re less aggressive than straight acid and usually have detergents to help lift residue. Fine if you want the foolproof route.

Whatever you do, protect the grout. Acid eats cementitious grout quickly. Mask it off or avoid direct contact.

Better to prevent it in the first place with proper water chemistry.