Don't know alot about 400watt HIDs but I know they crank out a fair bit of heat. That combined with trichome rich buds is going to create a lot of smell. My flap idea may not be suitable in this situation. You may need to think about cooltubes and carbon scrubbers too.
elcheapo Reviewed by elcheapo on . Intresting Grow Room Set Up With GOOD PICS! My Grow Room Setup. Like to know what people think. also included in room: Digital Thermo-Hygrometer, Combo Nutrient and Grow Room Thermometer, ADWA EC Meter, soil dampness meter, PH Meter. the room isnt big but should be able to grow 3 plants. walls to be coverd in mylar and white/black reflective sheeting. Anyway love to know what people think or if we could make it better. Rating: 5