My pool store has often indicated to me that the balancing is slightly different for winter balancing. Basically what they have always had me do is to boost the calcium hardness up to a range between 200-275. I've gotten to the point recently (as is indicated in many of my recent threads) where I have started doing my own testing rather than relying on pool store advice. It does seem, from looking back at my store water test printouts, that by the time I was ready to close often my CH was well below 200. I have been reading some of the sticky notes here about closing and don't find anything indicating that the levels during winter should be any different than during summer. Thanks for any advice.