Thanks for all advice, my tent is currently unzipped slightly to allow fresh air as my c02 is in the mail right now, should be here by weekend which I planned on running 1300 ppm but I don't have it yetI know this doesn't answer your question but you are probably better off venting at least once every few hours. It'll probably be the most efficient way to lower the humidity and I know you said you can't vent to keep your temps up but your plants need oxygen as well. Do you have a ppm meter? Just tryin to help figure out the most efficient way to keep temps,humidity,co2 in line. What is your humidity at without the the dehumidifier. What's your co2 ppm if you know it?