My 7yr old felt something sharp today, when the pool selltled the edges came off the tarpwe had under it. Theres a rock or something under it so before it pops the pool I'mdraining. I'm expecting it to take about 7 hours to drain through the hose. When we fill it again in the morning what should I throw in as soon as I fill should I just test the water then add whats needed I use BBB.