Have 6’x9’ veg area and 4’x4’ tent. Wanted to get co2 at floor level back up in room. Bought 4 GDSTIME 120mm squirrel cage electronic cooling fans with speed control off of Amazon for $21.00 each. Mounted them on wooden stands with exhaust pointed up. Put 2 in veg and 2 in tent. Raised co2 ppm at canopy level by 20 percent.