Wow 40rh when buds form ****...idk if I can get it that low even with my dehumidifier.At this point I aim for 78f and 50-55% humidity. This is the ideal time of year that I don't need to run ac in the tent. Later in flower, and when I need to use ac, I control it at 72-75f with lights on. Once buds start to form I'll put the dehumidifier in if/when necessary and keep rh at 40%. Lights off temps I just let ride until late in flower where I'll drop temp to 65-68f during lights out.