Great stuff or Waterfall foam

Im planning on doing a great stuff method for a viv thats gonna house day geckos( a little aside from dart frogs) and I would like to know what foam you guys like to use( cant do clay because day geckos dont like as much humidity as dart frogs) but anyways whats better black waterfall foam for ponds or grear stuff and is one more safe? thanks oh and expect a frog room thread around easter I finally got around to doing it