I've had zero problems with my chemicals all summer. I've never had a hint of combined chlorine. I'm winterizing today and suddenly I have combined chlorine.
What I did:
1) I brought the PH down to 7.4 and added 7 of the 121 oz bottles of Chlorox 8.25% bleach from Costco. Measured Chlorine at 33PPM 5 hours later.
2) Circulated water for 24 hours and added 38 oz of Polyquat 60 as insurance
3) tested Chlorine 24 hours later and it is now at 25PPM with some combined Chlorine.
I have a salt pool with a CYA of 80. I kept my Chlorine at 6-8 all summer and I don't have any algae and never had combined chlorine until today. I think when I brought the pool to shock level and added Polyquat 24 hours later, the Polyquat was simply oxidized and created combined chlorine. My question is now what? I was going to cover the pool today and blow out the lines. Is it ok to do this with the combined chlorine or do I now need to SLAM to get rid of the CC which was created by the Polyquat 60?