I normally use the Pool School instructions for closing my above ground pool. This year, however, I will have to fully drain the pool within the next couple of weeks in order to make repairs to some of the metal parts. My plan has been to drain the pool, make the repairs, then order a tanker of water (9,000 gallons) to partially refill it before putting on the cover and closing for the winter. The water is trucked in from a municipal source, so it's clean and chlorinated.
My question is how to treat the water before we put the winter cover on. The pump will have been disconnected prior to draining. Should I add chlorine or algaecide during the refill to prepare the water for the winter? Do I have to worry about having 0 CYA before closing? I am in central Illinois and we're expecting daytime temps in the mid 70's and night temps in the low 50's for the rest of the month.