My filters are hooked up to the fans, they just have a longer duct drawing the air through them keeping the added heat from the fans outside the tents.. In the winter it doesn't make any difference, in August, there is no questions that it helps to keep your temps lower. There should be two fans per tent. One for the light loop (can and should be dumped into the house for the free heat) and one for the carbon/temp/RH loop (can be used the same way if your filter is new). The latter should be run off an enviro controller able to link (bridge temp/RH at least) functions on a single outlet. I use Sentinel CHHC-4 controllers because they are the best IMO, but you can use anything you want with similar functions. Keeping your carbon fan on low (easily adjusted via the controller) 24/7 will keep a negative pressure in the tent and keep your odor down considerably.