Thanks guys. Just a few more tanks and all of them are equipped with a background. I like this last one, but I prefer my H. orientalis background though. After a while the grout gets covered with mosses and dirt and it looks way more realistic. Shrimp love to hide in the cracks and the snails search the surface for tasty morsels. I'm now working on a P. ruber background at this moment. Above the surface I made use of concrete binder adhesive (Flevopol) mixed with fern root grindings and turf pulp. This gets covered with moss if you rub it in with Java moss and when everything remains humid enough. I've applied it on expanding foam like clay. I use this for my frog and gecko vivs. Water will flow over the fake rocks on the left. In the middle there's room for some plants and on the right I've used some cork bark.
I also noticed that you mentioned that you use a Flevopol enclosure for your P. ruber. I also have a group of them, and I was thinking that when I finally get around to making a nice naturalistic vivarium for them, I would definitely need to use the Elastopur, not Flevopol, because plethodons are so sensitive to the quality of water in their seepages. Am I wrong?