I'm in Phoenix so it is generally really dry here. I manage to keep rh in the tents to 45 - 50 or 60 range despite there being an ambient rh of zero most of the year in the rest of the house. Temps in the tent stay in the the 70's. I pipe AC in when it gets too high. I've been fortunate, I've never had to run a humidifier, and when it gets too humid I just run the AC or open the tent and let our dry heat suck up the excess.