Quote Originally Posted by stinkyattic
Air flow direction has to match up. I'm not sure if those have integral booster fans in them but if they do, check the direction and mark it on the thing somewhere.
Hi Stinky! These are 18" glass, 23 1/2" overall, Hydrofarm cool tubes. There's no fan in them. I'd think that people using multipe cool tubes have probably experimented with different configurations to get the most even light distribution - which is my concern here.