I'm a little confused about...
1) whether I should lower the pH now. Most recent test results on 7/31 before I started shocking:
FC = 8
pH = 8
TA = 48
CYA = 60 to 70

At this point, I'm only testing FC as I know that pH test won't be accurate. So, should I lower pH based on it being 8 (before shocking)?

2) what is mustard algae shock level for CYA of 60 to 70? 35 to 40 ppm per TFP chart or 42 per your message? How long do I maintain that level?
Thanks.