The driftwood log I have in my Green Tree Frog's tank has begun dripping some sort of residue into the water dish below and its got me worried. I went to a petstore to look for a replacement, and when I asked the owner about this he said it was just substrate and other things like oils or somethig dripping off the wood during misting, and that its not harmful for the frogs. Is this true? Anyone have any idea if this is true? Or any other insight as to what may be dripping off the log as well? If its not hurting them, I don't want to have to replace the log just yet and deprive them of their hiding spot.