i keep my gerbils in tanks full of peat moss with about 5 inches from the top
of the tank; i dont use supports, but they've never had a collapse, i just
pack it down real good, and i NEVER put water in it! that just makes the
seeds grow and the body heat in the tunnels causes bacteria: peat moss alone
if packed fairly tight doesnt need water to hold up (my tanks are regualr 10
gallon, i'm not sure about bigger ones, i would assume u would need supports
thought).... so far i have just let my gerbils figure out burrowing on their
own, and they all go to the bathroom n the same corner (usually on the
opposite side of their food) its kind of cute in a disgusting sort of way
that i look in the cage to see an isolated little pile of droppings!
