I honestly though the pink stuff was limescale! I get it off with that Viacal stuff ...
Anyway - @Peachy2005 - i've been there, in the mouldy rented house being told to keep the windows open! 🙄
4 years. Summers were fine. Winters - one big damp management situation.
So firstly - the house has a problem. Black mould is not normal.
I found you have to keep the windows open a crack and keep the place warm and blitz the mould every 2 weeks or so before it built up too much.
Bleach does it. I used to mix a solution of cheap thick bleach and water in a spray bottle (empty flash spray bottle or something). In the kitchen i could move everything out of the way and literally spray the ceiling corners and it would drip. I wore rubber gloves and a shower cap and had the window open to let the smell out. Wipe worktops down afterwards ect.
In the bedroom i would have to just chuck an old sheet over anything i couldn't shift and get up on a step stool and spray as close as i could. The house was normal height ceilings so i could do it.
When the wall paper round one of the bedroom window reveals (the bit of wall at the side and top round the window) got damp and peeled i pulled the whole lot off, damp and not damp. (I made a neat line with a sharp knife where it met the wall paper 'in' the room) cleaned the whole reveal with mould killer and when it was dry i painted it over with cheap white matte bathroom emulsion paint. That bit then stayed mould free for a whole winter. Our last winter there.
It's a fucking shit way to live and i feel for anyone in this situation.
If you have a tumble dryer or heated clothes dryer use it. Dry your clothes in the warmest room of the house if you can. Keep the damp rooms warm and mould free constantly was my best solution.