New SWCG and strange FC/CC readings

[Furbabyvet]

Sigh. I thought this was going to be simpler after installing the Aqua-Rite t-15 SWCG on our 11,400 gallon pool. Here are my numbers. I hope someone can give me insight as to what is really going on.

5/17
FC 9
CC 0.5
TC 9.5
pH 7.8
CH 625
TA 80
CYA 70
Borates 50
NaCl 3600

We just had the SWCG installed and are still trying to find the best percentage to run it. Also put on new floating solar cover to warm up pool. Pool looks clear. Water is around 78 degrees. I was dismayed to see the CC, and figured I better shock it before I lost the war. On this day I added a gallon of 10% Cl and a couple cups of 28% muriatic acid. Also turned the SWCG to superchlorinate for one pump cycle of about 7 hours. I admit I didn't retest the water immediately so I don't know exactly how high we got the chlorine, but I'm sure it was at least 20 based on the fact that 3 days after shocking:

5/21 7 a.m.
FC 18 ppm
CC 0 ppm

Removed cover in morning to let Cl. drop so we can swim on 5/22. Dropped SWCG to 10% (from previous level of 30%) for overnight 7 hour pump cycle.

5/22 9 a.m.
FC 14 ppm
CC 1.0 (!)
I put in 2 caps of leftover PhosFree (we bought it before I found this forum) we had just for kicks. Solar cover off, pump/SWCG off, full sun on pool. Still hoping to swim this afternoon.

5/22 4 p.m.
FC 13.5 ppm
CC 0


The water is very clear, but I'm never sure if it has a greenish cast or not because the pool has a brown Pebble Tech finish and it's kinda hard to tell the exact color of the water. I can say there are some tiny specks of green at the waterline like we had last year just on one 10 foot section of the pool. Those have been there for a couple weeks.

My question is: is this some weird false CC reading having to do with the salt or whatever OR do I really have algae trying to bloom in there? Do I need to shock more? I would have expected the free chlorine to drop more than 0.5 ppm if there was really algae in there. I wouldn't think the PhosFree would be able to control an algae bloom that fast either.

Thanks pool gurus!
Tabitha