Well we got the spa up and running. It's an inground fiberglass and it was filled by city/house water. Intial pH was 7.2 and Cl was 1.4 ppm. I was reading where I should add baking soda first, target is 80-100 ppm for TA, and then check to see if the pH rises and then adjust that to ~7.5 by adding borax. Next step would be to add CYA to a 60-80 ppm level over 2 or 3 doses so not to overshoot.

Seem about right?