hello! I am interested in how much cfm ventilation i need for my grow box grow box size 0,40 x 0,40 x 0,80 (m) and i interested how large size need for carbon filter (homemade) ?? please help and what cfm ventilator need for pull out air through carbon filter..? Help! And i could use pc ventilator for pull out air through carbon filter..? very bad to go with the English language. Sorry..