Recently had an 18' x 54" round pool installed 07/2021 so we have not had a complete season yet with the pool as we had to close it in September of 2021...we live in upstate NY. Now my problem...was told by installer we did not need a winter cover as there are no trees nearby except pine trees. We did all the recommended closing procedures by lowering water level, balancing water chemicals, taking filter apart as described etc. Now my question...once my pool starts to thaw and there is no longer a coating of ice on top...what chemical should I put in and how much?? I should tell you we use BAQACIL CHEMICALS.