I seen a picture of a tent but now its gone was that yours? If so that filter is definitely to small for that fan. When fans arent moving enough air, they sort of "stall out" and even tough they are spinning, they move very little air. Looks like you connected a 4'' filter to a 6'' fan? I connect 8'' filters to 6'' fans to make sure they dont have to work to hard to move air.
You would have to program that thing to run something that would theoretically control humidity but you dont seem to have a real solution to humidity.