I've been thinking about grow boxes.. And it seems to me the best use of a carbon scrubber is simply to cover holes in your grow box with carbon activated filter sheets like this For a average size grow box, why bother with anything else? Those cannister shaped ones usually stick out of your growbox making it less discreet, and I don't see any practical reason to have a fan attached to it. To deal with airflow, you can just as easily have a flat fan right against these sheet filters and the growbox hole leading outside. Basically as long as every hole leading out of your growbox is covered by one of these filters, smell should no longer be a concern, no? Id like to hear opinions on this.
It works, I have them on my PC setup. I have one in the front with no fan for my passive intake. Then I have 2 more sandwiched between by case and fans at my exhausts. I get about a 9deg F difference between room temp and box temp. I think they will work pretty well as a light trap. They do restrict the efficency of the PC fans though, so make sure you get some high CFM rated PC fans to compensate.