Using Automotive Antifreeze in Black Grey Water Drains

Pops R wrote:
...the temperature dropped below 0 and so was just wondering what others do or use as the "Pink Stuff" from Walmart did not keep the sewer lines and gray water valves on the motor home from freezing up. In fact even though it says protects to -50 it has turned to pink slush in the jug when it got down to below zero...