I managed to lower the calcium level and acid level both by half. So now my calcium reading is 200ppm and the cyanuric acid is at 50ppm. I am using the chart from Pool Solutions that indicates the minimum chlorine level based on the temp/stabilizer level. With two gallons bleach in 30,000 gallon pool, I can get the free chlorine reading at 4.5ppm. I still have the black algae spots and not sure what I should use to try and get rid of them since I am not using cal hypochlorite shock anymore? I suppose just super chlorinate with the bleach to around 10ppm? Same thing as shocking with the granules, right?