Thanks to all previous posters on this topic: starting new thread as existing
long already. While not an SMB owner, I am "Some Other Brand" (Ford E-250) with
a real interest in the mods folks make here.
This past season's winterizing made me realize I needed to know overnight low
temps. There was no other way to determine the earliest that plumbing antifreeze
might be needed and in spring when the system could safely go back to fresh water.
That data logging is still to come, but infrastructure comes first!
I put this up on a blogsite as I may want to point to it from various locations.