I was laughing when I figured it out. I almost went with a 12' vortex. The 8" is serving me well. I'm getting a 6" vortex to run with 2 5' light tubes. I'll vent from outside to outside so I don't create a vacuum in the basement or need for more carbon filters I'll run 2 1,000 watt lights in each tube. Just have one set up now but am tripling available space next month.