Thanks for finally answering my question lol. i think the plants will do even better this time because last time there was no circulation in the room and they still did okYes you can run a fan/filter in a sealed room. Many many people do this and it works well.
Then you should consider adding CO2 if you don't have good ventilation.yea i know they need air, i wish i could have good ventilation but like i said it isnt possible at the moment so my only option is to open it a few times a day for air. i got maybe an ounce or so last time off of about 125watts.
I would suggest you don't and instead get passive intakes.Can you use a carbon filter/ Fan setup in a closet with no intake/out just to circulate and clean the air? I don't see why not, but just wanted to see if anyone has anything to say. i would also open the closet a few times a day just to get fresh air.