Pumping glycol fog through a 3/4" pipe risks reconstitution into liquid due to condensation, as fog consists of tiny droplets suspended in gas. Experts recommend using larger ducts (3"-6") to minimize this risk and maintain fog integrity. Smaller pipes may lead to significant condensation, potentially causing leaks or clogs, and reducing the amount of fog emitted. The flow dynamics change with pipe size, and while smaller pipes might still work, they are less efficient. For optimal results in a larger setup, using appropriately sized pipes is advisable.