A gentle breeze in a grow-space does a whole lot of good. It replaces the carbon dioxide depleted air from around plant leaves and helps to prevent hot-spots under powerful grow lamps. Air circulation is essential to a good hydroponics set-up. Choose from a clip-on type for a small grow tent, or a pedestal or floor mounted fan for larger garden layouts. Better yet, invest in anair diffusersystem, which does the same job to a much higher standard, creating an even environment right the way through the grow room, eliminating microclimates and reducing issues with windburn.