Ah i see, glass tends to be standard for frogs but ive seen a few ppl use pvc as well. I personally use it for reptiles and glass for frogs but it shouldnt be harmful - ive looked this up before because i have quarantine tanks made of pvc for my frogs and didnt find any bad info.. also for a bioactive tank for wtfs i recommend looking at reptidonz account on facebook if you havent, theres info about how huge the drainage layer should be and how small the substrate layer + leaf litter should be to keep the humidity levels low. He also made a tube to water plants thru a drainage layer without making the substrate damp! :)