Zinsser Primer, Sealer, Stain killer

ashe

My experience of Zinsser is get ready to see flashing if you just paint over it. When I've given it a sand before painting. it has worked much better and blended in well. I'm not convinced those are stains from the photo, from the texture it looks as if the paint hasn't had good coverage - after replastering did you mist coat it and then give some good coats of your chosen colour?

sol2017

From what I've heard 123 is not the best product for water stains but I don't speak from experience.

I've used BIN for water stains and it worked well. However, as per above, it was flashing big time. I did some light sanding after applying 2nd coat of Bin, and then after 4 top coats it was finally invisible 

WeAreGhosts

I had a decorator to do the painting, so no idea if he misted it. He painted the other bathroom too, which had also been replastered, and it hasn't happened in there. He should have done, but whether he did ....

I will try sanding before and after painting, I guess it can't make it any worse!

sol2017

Depending on the size of the wall, it might be worth considering covering the whole wall with 2 coats of Zinsser. More expensive but should hopefully give more even finish and won't require sanding and extra coats of paint.

The only risk here is that it's not clear what those stains are. But fingers crossed your sealer does the job