I attempted to use ms paint and draw what my current ventilation setup is looking like, because I'm pretty sure that I could have things arranged or setup more efficiently. I have a 315 CFM fan attached to my light reflector sucking out the hot air, and up through the ventilation to meet with the other exiting air for the the final ride going outside. Now, when I don't have my 335 CFM fan turned on to exhaust the air for my light, I can feel the other exhaust air leaking back through my light, which the diagram notes this behavior. When I turn my 315 CFM fan on it's first setting, that still is not enough to counter how much air is actually going backwards to my light, which it actually takes putting my 315 CFM fan all the way up to really move the air from the light to meet with the other exhausting air going outside. Could this issue be solved with a $15-$20 backdraft damper from lowes or home depot, or would I have to rework my ventilation setup entirely?