Keep making tweaks to grow box after each grow. Next up, improve ventilation. I have a small grow box (2X2X5) that works great for my personal grows. Because of need for stealth (spousal unit is paranoid), I am using one 85 cfm in-line duct fan, mounted inside an insulated box, along with one 40 cfm computer fan at exhaust opening and another 40 cfm computer fan at intake manifold. When plants are seedlings I have to block air flow at plant because it is too strong on tender seedings. Once in flower I connect carbon filter but worry about reduced air flow through filter (some say as much as 50%). Any suggestions for super quite exhaust fans?