Oh yeah, definitely will be doing a small circulationing fan. I'm brainstorming a way to siphon off some Co2 from the natural gas boiler and water heater for my house, maybe just a small hose from the ductwork to bring Co2 into the grow tent just to insure there's always a fresh supply.
WHOA! Do not siphon any exhaust gasses from any combustion appliances in your home! The primary by-product of combustion of natural gasses for heat in homes is CO, that is carbon monoxide! A very dangerous gas! Do not "siphon" any gasses produced as a by product from combustion in your home, this is a deadly gas, carbon monoxide, you want CO2, you will not find it produced as a by product in any appliance in you home. This is a patently bad idea, do not consider implementing this strategy!