Hi, i read the "shock your pool" in pool school, but i'm still not understand all. For example my CYA is 40 and then my shock level will be 16, so i need to keep adding chlorine at 16 ppm and until my water is clean and CC less than 0.5. My question is before I put the shock to my pool, do i need to add FC to 16? or if any number (like 10, 12) is fine? Because the overnight test will perform on morning and the best time shoocking is at night. It will lose some FC during the morning and afternoon.
Also I bought the Hth super shock N swim shock, it is 1 lbs per 12000 water. If my pool is 27000 gallons, if i OK to use 3 lbs? or i need to use 2.25 lbs only? If i use more shock, did it damage my pool? My pool is vinyl liner.