Okay so this is my first time growing in a tent so I’m a little out of my element. Up until I switched my plants over to flower I have had no problems with my environmentals. I have recently been having an issue with keeping my RH low enough in flower. While the lights are on, it keeps the humidity right where I need it to be but as soon as the lights go out it spikes to 80%. I have an in-line fan in the bottom I’m using for an intake and also another inline exhausting the tent. I have an AC unit outside of my tent as well to try to keep the temp and humidity down but it seems to only help in the day time. I have also bought a small dehu for inside the tent but it’s honestly doesn’t seem to be doing shit. If anyone has any suggestions on how to keep my RH down at night I would be so thankful. My plants just hit week 3 in flower and I don’t have long before this issue is going to start to rot my buds out. Also if anyone has any suggestions for a dehu for a 4x4, maybe the one I bought it just shitty.
I use either a dehumidifier, a humidifier or nothing depending upon time of year. Summers can get humid, and the furnace makes dry air in winter. You have to condition the air OUTSIDE your tent where the air gets drawn from. Running anything inside the tent would be pointless. If you have proper air flow, you should be changing all the air in the tent 1-2 times a minute and any humidifier/dehumidifier simply would not have time to affect anything. In my case this applies to temperature also. In flower stage I have to keep my tent room(whole house,lol) about 68 degrees or my tent gets above 78 degrees. For me that's a tad chilly, but it's only 11-12 weeks at a time and I deal with it because the results are fantastic. Whatever room your tent is in will determine conditions. For example my basement is cooler, but way too humid for a tent, so it has to be upstairs.
I have a relatively large dehumidifier that runs when the lights are off after flowering gets underway. It is outside the tent and dehumidifies the air of the entire room so that when you pump air out of your tent you are getting dehumidified air in the passive intake vents. It only runs during the dark cycle because as you've noticed the light does a good enough job of lowering the RH and also because running the dehumidifier will significantly raise the temperature.
