Antifreeze?

50/50 water anti-freeze is far less effective than pure water at exchanging heat. Pure water with a surfactant such as Water Wetter is even better. Thing is you won't have any freeze protection.
I suggest you use water and a surfactant as the directions say, and add a small percentage of anti-freeze to protect when it freezes. Some anti-freeze also has some anti-corrosion additives.
You won't need much Water Wetter, read the directions.

If you can find Engine Ice, it's mixed and ready to go.