Maybe I'm wrong? But I was thinking on 16,000 gallon pool 1 gallon Cl would raise 8ppm. We just recently bought the Lamotte Color Q 7 digital test kit. It is a liquid test kit, works great, no more guessing at colors, it gives you a # to go by. The mother in-law loves it, she didn't bother to check her readings before very often because it was always a guess what the color was. She just took samples to town & let the pool store tell her what she needed. For 20+ years, imagine how much $ she dumped into the pool. The local pool store will probably go out of business now that I've banned her from going there