The FC is far too low for CA of 80ppm. Minimum of 5ppm - closer to 8ppm would be better. I'd pour in two jugs of 8.25% bleach just to start.
pH is kinda low, bring it up with 20 mule team borax from the laundry aisle. Start b adding one box, let it dissolve and mix, test again, add more as necessary. If you put it in the skimmer, go very slowly, borax can clump up and form a rock hard plug.
Ignore the wheel and the booklet - they are very confusing. You needn't worry about negative saturation index with a fiberglass pool.

Here's a hint: If you use a 10ml sample for the chlorine tests and multiply drop count by 0.5ppm you'll conserve your test reagent. Also: if one scoop of DPD powder turns the sample pink, you don't need another.