Metal in the water (Fiberglass 35K pool)

[blk133]

Hello,

I think that I finally figured out that I have a metal stain in the pool.
I took one little Vitamin C and droped it on the stain, in about 20 seconds I could see a white spot around it. (See Pic before/After)

Now if someone could tell me how much of Vitamin C powder do I need to treat a 35000 Gallons fiberglass pool.

My pool was green a week ago because I went on vacation and nobody took care of it.

After I returned I tried to shock it.

For the last 3 days water was at around 12-13 PPM every night, but during the day it would drop to 5PPM so I would add more chlorine at around 6 PM.

My problem is that I don't have anyone to test it 3 times a day.

My current numbers are:
PS233 kit

FC 9PPM
(was 15PPM before I went to sleep, 12PPM when I woke up, I added 3 QT of bleach and now it is at 9PPM) Temp is 77*F Pool was open for the whole day with the sun.
So:

FC 9PPM
CC .5 (maybe less)
PH 7.2
ALK 80-90
CAL 120-130
CYA 20-25?

Please help.
Thank you,
B.