Fog fluid getting a bit expensive or you are like me and need to run fog machines for 4 hours a night for an entire month. Here is an easy guide to making your own fog fluid.
Vegetable Glycerin (99.7% or greater purity)
80% Distilled Water
This is my ideal mixture (by volume). You can vary your glycerin to water ratio as low at 10/90 and ratio as high as 30/70.