Hey everybody, i'm new to the site and loved this thread because i'm thinking about doing a rock wall to my ten gallon nano, which i hope to upgrade to a spare 14g tank. There seems to be a debate about whether or not to use great stuff, so i was just wondering if there are people that use it with success? I personally am not sure..i have used it before and noticed that it gets pretty flaky when when it sits in water. I have read on another forum, when i tried making a terrarium, that peoples geckos and frogs were dying mysteriously so i do believe there is some truth to there being something wrong with using it. Although, on the other forum it also said there are two kinds of GS and that one is safe and one is not, but i forgot which kind is safe. Besides home depot and online does anyone know where i can find the pond kind of foam?