I have figuire this out a month ago. If you use clorex floor cleaner, Scrubbing Bubbles tub cleaner 2/3 filled hot water or warm water in tub & a motorize scrubbing brush like the ones with Dawn written on them. You can get mold, mildrew, soap scum, old cauldon (sorry about the spelling, I mean the white stuff that people put around the tub that drys on it for years) off of the tub. It might take time but it will come off. And I didn't have to use bleach, I didn't have to wear gloves, mask or goggles. I save some money doing that too.
Pam-Doggirl3