If you use Dichlor powder or Tri-chlor tablets, watch your pH. Both tend to push it down. But bleach and cal-hypo won't have that effect, and cal-hypo will add calcium, which you, with a gunite pool, want to be between 200 and 400ppm--you are a little low. Calcium protects the walls and keeps calcium carbonated from leeching out. Useless on vinyl and probably useless on fiberglass.