I'm going to do some Ozark Trail maintenance this weekend, Chance of freezing at night, little chance during the day. I decided to not bring the sawyer filter. Too much trouble keeping it warm, I'll bring extra water & aqua mira. So I'm thinking as a general rule I'll use aqua mira if there is any chance of freezing. And have the filter sent to me after the chance of freezing is gone.
I know about keeping it in your pocket or under your clothes, in the sleeping bag
What do you do to insure clean water in freezing temps? & the integrity of your sawyer filter.