I am another one who opens with little or no CYA every year. Pool is closed in mid-October with a winter cover, is frozen several months, and, around May 1st, I always open to a clear pool, with little or no Cl and CYA. To reduce maintenance now that swimming days are scarce, I am running out the season with pucks, as I know from experience that whatever CYA I am adding will dissipate over the winter.

- Derek M
PEI Canada