My veg tent is 5 feet by 6 feet and 5 feet 10 inches tall. I used this oil diffuser to raise the RH, it went from 53% up to 63% within 20 mins and is fluctuating between 60 and 63 now I might add another one to bring it up more. This one plays sound, which is neat, birds and shit, it also turns off when empty. I think I could add some mint oil to deter bugs. I took this from my wife, good news is she doesn’t get on this site and I will never tell her what happened to her diffuser….lol. I had another idea of getting one of those potpourri things with a candle, cause the water vapor will add humidity and the candle will add about 10 grams of Co2 an hour. Also another thing I learned is that Co2 is very dense and typically sinks to floor level, this is why basements typically have a higher Co2 count. That being said one could assume that when Co2 is introduced into a grow room, it must build up from floor level to reach plant leaves and such. I could be completely wrong but if this seems logical then building a raised floor with cutouts that your plants can slip into, could increase the chance for Co2 to start building at soil level and could be a good way to keep soil cooled off if you run a hot room.