Hey Brian,
almost all of us south of the Red River keep our pools open. Just maintain it as ususal. You will find your FC demand decreases dramatically due to the cold water and much shorter days. And so you won't have to test as often.
We do recommend though, that during the times the temp is at are near freezing, to run the pump and keep the water circulating. Moving water doesn't freeze as quckly. For no longer than we see freezing temps, that's about all we need to do for winter.
Of course there are a few that shut it down and cover it, but there isn't any real need to do that.