Oh, now I am really confused. The FC reading is now ZERO!!! What's going on? It was holding steady until I started adding more. I even diluted the sample to see if it was getting bleached out and it still said zero. I happened to have a crummy old test strip so I used it to cross check and it is reading 20+ ppm chlorine. The water does not look better. It might look a little worse now than earlier today. Any suggestions?