Thanks, BB; I know I could just run it in a tank to keep it going, but my question is about whether it needs to be operational with water moving through it. Would the normal water movement of the tank (other filters working) be enough to keep bb alive in a sponge removed from the housing and tucked behind some plants, for instance?
I have used gravel and rocks, etc. to transfer bb to a new tank, but the sponge would hold way more bb--but would it be enough to ensure immediate cycling in a 10 gallon QT tank?
In the past, my QT tank has pretty much always had a resident (or six!) but as I get my tanks stocked the way I want, it would be empty a lot, but I really don't want to run another air pump in any of the display tanks…