Tom and all,
Yes, I suppose it would have to be non-poisonous or there'd be cross bones and warning labels all over it. Still it kind-of freaks me out to think of consuming that stuff. Maybe it's a natural fruit punch, not only safe to drink, but nutritious too. They are simply missing the percentage of real fruit juice, ha, ha.
Like you say, it's all about freezing/expanding of the water . Square bottom water tanks as we all have would likely see a little stress from an inch of frozen water. Too bad the inside of the tanks don't have a nice radius to pop the ice upward as pressure builds.
Actually I should have a lot less than that inch of water. I do angle the rig on a steep slope at home so more water finds it's way to the corner of the tank where the drain is. When our well water is left standing for months at a time, a bacterial clear slime will form on the sides under the water line. Less water = less bactria. Spring time disinfecting is essential in RVs. Our old rig had a carry-on 7 gallon water jug for on-board water. If I forgot to empty it in the fall, it was all slimed up inside.
