The ratio to make fog juice is 3 parts vegetable glycerin to one part distilled water. So for every 6 ounces of vegetable glycerin you would need ¼ distilled water.
Measure out distilled water and vegetable glycerin with a measuring cup. Add to a clean, empty container with lid using a funnel or pouring into container.
Secure lid and shake well to fully mix together. Label the bottle "fog juice" to easily locate it an not mistaken it for something else.
Give it a good shake each time before using in fog machine.
Notes
Store homemade fog solution in a clean and empty container. Keep in a cool dry place.