Ya, the overflow is a bit easier to glue to once it starts getting some coraline and other things growing on it. I just use a big glob of super glue. If the surface of the overflow is smooth, it will help to rough it up a bit with sandpaper or something along those lines. The glass however is a pain, and I havent been successful with that yet. I can always get it to stick for a while but eventually will fall off. Managed to get gsp to grow up it by sticking it right up against the back wall and letting it grow. It too forever to do so, but growing pretty good now. Even my giant Idaho grape monti that is growing up the back glass is not actually attached and would come away from it easily except that its also firmly attached to the overflow