An input to the LSI and CSI is temperature. Because of that, the same chemistry values used during the summer which produce a balanced index, lead to a corrosive index as the water temperature plummets (Thanks Bering sea storms <G>)
Increasing CYA is not good, because that takes CSI more negative
Increasing TA will make it less negative, but obviously that's going to affect your pH swings
You could increase your CH, but that has a fairly minimal impact on the overall value.
You could let your goal pH stay higher, from say 7.6 to 7.8
There's a similar set of statements that cab be made about LSI
So what do others do to compensate for the colder temperatures and still keep everything balanced?!?
Now know that last winter, the pool was so abused by the pool service people who showed up once every 2-4 weeks, dumped in a gallon of muriatic, and left and came back 2-4 weeks later.