The vortex and other "centrifugal" fans build pressure when they run because there is very little to no space for air to bypass the fan. This builds negative pressure on the suction side of the fan and positive pressure on the output side of the fan. If you don't have the room inside the grow space, you can connect the filter to the output side of the vortex fan (I have 2 of these) and the input side to the cooltube, either directly or with flexhose. Most of the carbon filters on the market today will work in either direction but seem to be generally better when the air is drawn through from the outside. But for smaller operations, pushing the air from the inside should be fine.
Ideally it would be better to set it up with the fan and the filter on the inside where the inside air can be pulled through the filter first then pushed through the lights and out. But the grow space often dictates this setup. I used to have my tents set up with the fans 10' away from the lights and filter, with the filters being inside the tents I was using, and it worked quite well as long as I had good passive intakes. There are multiple ways to do it, just make sure it eliminates the odor and keeps the proper temps. With the vacuum pressure that is generated by the centrifugal fans, having multiple bends in the flexhose is less of an issue as the vacuum pressure can overcome the turns. I am sure however, it does slow down the air flow somewhat. It then becomes a matter of how much is it slowing it down. For a smaller system, its probably not much of a factor.
