the best way to clean soap and hard water stains from the shower is to run a hot shower. then spraying mildew spray and vinager helps to soften the scum. afterwards, using a hot water bucket and a scrub brush, scrub along the grout lines and rinse with the hot water to wash it down. repeat daily with each shower, a little at a time, to reduce work spent on the shower.
Dawn & Vinegar sprayed on it and scrubbed w pad Prevention...Wipe down shower walls after each use. Use liquid soap rather than bar soap.
I’d say a really acidic cleaning agent, like bleach. If you find that to dangerous (which I personally do), you could substitute it with really strong dandruff shampoo. II’m not going to suggest any cleaning products because I’m not 100% sure of what to use and whether it’ll work. Sorry 🤷♀️