You're going to have to install it properly, as if for a finished basement.
Then run the dehumidifier IN the space.
Intake air will still be moist from the basement.
A 'sealed room' with CO2 boost may in fact be your best bet here if you can't get your %RH down below 45.
And btw... I'm a 'sis'
stinkyattic Reviewed by stinkyattic on . New growth is very pale! HELP i just started flowering two days ago and all of my new growth is a pale green, almost yellow looking. can anyone diagnose this? Rating: 5