Finally cleaned all the junk out of the pool. It got way cold here over the week, had to take a break. I kept dumping bleach in the pool though to keep the FC up. Poured in a gallon of acid yesterday so will test again today. I will search here for the overnight chlorine test , but it seems to hold pretty well overnight when I test in the AM. If that's what it is. I would like to get my SWCG to start making the chlorine for me, is it too early for that?