I'm a new in-ground pool owner. First when the pool was opened it had some brown \ green spots. I shocked it with Powder PRO and it all cleared up, but some very light brown spots remain although they get lighter and lighter. Also, it seems like vitamin C removes the brown, but not right away but if left for some time. According to water tests I don't have metal.
I have some of these dots in the pool that are hard to get rid of. I had a lot of small black dots in one place, but rubbing them with a chlorine tablet cleared most of them away. The green ones don't go away when I rub with chlorine or brush.
It seems like if I got more of these dots when I forgot to shock my pool one week and shocked 4 days later and the weather was hot (in 90s F). (I shock my pool every sunday)
Also, I have this yellow dust that disappears in water when I brush it or even when I just move my hand over it. I don't think it's sand. What can it be? I'll take a picture during the day and attach it here later