So here are my latest number:
FC: 1.5 (tested in the evening before I added more bleach)
CC: 0
Ph: 7.8
TA: 90
Hardness: 190 - 200
CYA: 40-50

Question:
I have some stain (yellow) in the bottom of the pool around the main drain. I think it is from last year when the pool was not opened (i bought the house last year).

Also some rust looking stains on the top tiles of the pool.

Any recommendation on how to approach these?