I was @ Lowes yesterday and they had these generic Active Carbon Filters on sale.
A 20 x 25 for $ 2.39 ?? Can this be true? Does it work? So, I took one home and I cut them into 4 x 4 squares, stacked them and measured it, built a box and mounted a fan in one end put the carbon stack in and screwed it to the side of my grow box where I have a hole. No smell this morning. How long well it last is my next question.
Peace