How to get pinky residue/stain off shower floor

[3summer]

Spent the day deep cleaning my parents bathroom
which has got into a real state due to disability/illness. It’s been a get in there with a toothbrush kind of clean as every nook and cranny was grim.
Theres a build up on the shower floor which is a pinky brown colour and I can’t get it to lift. I tried HG bathroom cleaner, then HG degreaser, then anti bac and finally bleach but nothing worked.
I’m going back tomorrow to finish off before they get back from their holiday. Any tips?

I wonder whether it's limescale that's become stained. I would try viakal or similar limescale remover left to soak for a while.

HG Mould remover if it’s stained with body fats which usually end up orange / pink

It sounds like a biofilm from the bacteria Serratia marcescens. It feeds on soap residue. Google "how to clean pink mould" (even though it isn't actually mould) to find the best way to clean/disinfect whatever the shower is made from.

That is S. marcescens too. It feeds on body fats as well as soap residue 🤑

Mould remover that bleaches the mould maybe. I got some recently from home bargains and it has been really good on spots of black mould.

Cif cream cleaner in the yellow bottle. Pour on liberally leave for 10 mins then rub off and rinse.

We get this and it's limescale. I leave it soaking in Vilkal or similar for a few hours then scrub.

@GingembreThe yes! I’ve just Google image searched and that’s what it is. Thank you everyone so much for your help. I should hopefully be able to sort it tomorrow now.