We have a white stain around the outlet. Have tried various shower cleaners, vinegar and bleach. Starting to think the tiles are faulty
226100cookie-checkShower floor tile staining
Shower floor tile staining
Chemistry in the real world
Probably mineral build up. Hit it with some sulphamic acid. BAM Easy Off is the stuff you want
https://www.woolworths.com.au/shop/productdetails/252241/easy-off-bam-power-bathroom-cleaner-grime-soap-scum