Originally Posted By: Dave Davidson1
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You know that windshield washer anti freeze that is supposed to protect down to zero degrees? I put some in the toilet tank and bowl to keep it from expanding and breaking. That's after I get most of the water out. That stuff, blue in color, was frozen to a really hard slush. What do you guys use for something like that?


Dave,

Lots of products on the market cheap. Here's a link to one.

https://www.walmart.com/ip/Super-Tech-RV-Marine-Antifreeze/17179674


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