As long as you open the door to the room the plant is in once a day it will have enough air exchange especially when its that small. What kind of light are you using looks like a regular compact house fluoro light i have one in my room lamp. Day eight looks kinda weak make sure the light isnt to close depending on how hot it gets. Final piece of advice make sure you have holes in the bottem of the tub for drainage or else your roots will rot with mold.