Tics

Ah.. I see. Thank you for your advice and sharing!

Hi everyone, I just moved in. Recently, there are white calcium stain on my toilet tiles and grout (as attached). The tiles are homogeneous tiles, with those"rocky", uneven surfaces. I've tried scrubbing, spraying water, vinegar + baking powder, but it didn't remove the stain. Once the tiles are dried, the stains show up. Anyone knows what is this (limescale, soap built up?) and how can I remove it? Thanks!