Spring opening question

We moved into a new house with a 36K in ground vinyl pool. The pool was winterized last fall and had a solid green winter cover on it all year. I opened the pool myself this spring and all was going well until about after 5 days the water cleared up and looked good but there are spots on the floor. Of a black dusty looking alge from the size of a quarter to the side of a tomato.
I used liquid chlorine shock to open the pool with and here are my readings from my kit. I purchased the kit here last year.
FC 2
CC .5
CH. 200
TA 60
CYA LESS THAN 20 (dot never disappeared)
PH 6.8
Chlorine 1
I would love to use the BBB METHOD IF POSSIBLE. Any help would be greatly appreciated.
Temp is 65.