+1+1+1+1 on the titebond iii. I love the stuff. 90% of my 125 paludarium and 100% of my 20L paludarium are great stuff covered in coco/titebond mix. And the best part about titebond is that if you end up with any bare areas, you can go over them again. With silicone, one it is cured, you can't add anymore silicone on top of it since silicone adheres to almost everything except previously cured silicone. It also has the advantage of being able to use damp cocofiber as well. When using silicone, i have found it to be essential that the cocofiber b completely dry before pressing it into the silicone.