I'm not the expert by any means, but,,,
With CYA at 80, you need to keep your FC above 5ppm ALWAYS. This explains why.

http://pool9.net/cl-cya/

More borax is in order, pH should be 7.2 - 7.8.
Since your water is cloudy and you said FC was around zero, you very likely have an impending algae bloom. If it were me, I'd run the FC up to 20 or 25 ppm (with bleach or liquid chlorine) and keep it there until 24 hrs after,

1. There is less than 1ppm loss of FC between sundown and sun rise.
2. There is no more than .5ppm CC present
3. There is no hint of green in the water.

There are lots of reasons, other than algae bloom, that water turns cloudy and it is entirely possible that algae is not the problem. Bleach (liquid chlorine) is the least likely to complicate your issue if algae isn't the problem, and a little time will solve the high FC issue.

Good luck

Pappy