Generally, tree frogs will burrow into the substrate if there is not enough humidity. 50% i believe is a little bit low for a WTF. Try raising the humidity to 65-70%. I believe the pet carrier will be OKAY for a month untill you get a terrerium. another thing i think may be a problem, I have have 75w for my leopard geckos, and the bulbs get up to 90 degrees, so I believe that is why he getting down lower is to stay cooler. and i would prefer( not saying its a need, but im picky about substrates ) about an inch or two of eco-earth or plantation soil by exo-terra and zoo med. If you have any more questions about caring for WTF's, inbox me here at the site and i will reply as soon as i can, Peyton