I spend some time filling my tractor tires with RV antifreeze. This is a potable liquid that has a freezing point of -50 degrees, and weighs about 9lbs per gallon.

Air/Liquid adapter: https://amzn.to/2ILrmp7

Main Camera 1: http://amzn.to/2EmNfJS
Main Camera 2: http://amzn.to/2Gqyqqd
Action Camera : http://amzn.to/2E0dTub
Microphone: http://amzn.to/2nqDX7h
Studio Mic: http://amzn.to/2Enb1oP