I understand the worries, first year I had the TC I only ran pink stuff through it trying to chase the water out with the pink stuff. Didn't feel good about it when it got real cold. Now I do both rigs by:
Blow lines to clear out as much water as possible
Run pink stuff through
Blow lines again blowing pink stuff into traps/tanks
Sleep real good with no worries.
It reduced the pink stuff usage as I was having to run lots through to ensure it wasn't diluted and it makes getting it all out in the spring pretty easy. Just flush, then blow the water out and flush again, turn on the WH bypass and fill everything up, no taste or foam at all.
Stay warm, heading down to single digits again here also.
Dave
'99 Alpine 36SDS/8.3 ISC 330 Cummins
Or
'05 Lance 845
'06 Super duty SC/SB 6.0
Upgrades include: StabilLoads, Air Bags & Timbrens,Swaybars
Usually towing an '01 Wrangler, lifted/locked on 35"s or a mildly built '98 Cherokee on 33"s (only one locker)