Exactly what I need! I'll be building one this week (the bucket style). We'll put it through a torture test in my rodent room. If it can control the smell in there it will be worth it's weight in gold! The building is 7ft x 9ft with a 7ft ceiling, and houses around 2000 rodents!
6.13 Corns, 4.5 Ball Pythons, 1.0 Mex Mex King, 1.1 Mali Uromastyx, 1.1 Red Saharan Uromastyx, 0.1 ETB, 1.0 Boxer
is the open channel down the center necesary like does it help air flow or something? because couldnt you save your self some trouble if your making it yourself if you dont make the center chamber.
Not sure if anyone reads this thread still or not, but I was wondering about using charcoal briquettes for this? I looked around online and although it's clear you wouldn't use it in aquarium filtration, it appears that it's commonly used by people to control odors in garages and storage sheds. I know carbon is relatively cheap when used for this DIY kind of thing as opposed to a prefab filter, but the amount of carbon to fill a 2gallon bucket is still a bit more than I would want to pay sadly.