This is the first Vivarium so the substrate is coco fiber and Sphagnum with leaf litter. We were planning on changing it to ABG in a larger build soon but we might just have to change the substrate in the small viv we have and make some fixes of the rookie mistakes we hoped to fix in the next build. because right now life has thrown us a curve ball that will keep us from getting the bigger Exo-Terra for a while.