Really, really. really wish people would read every page of a thread before 'jumping the gun'. So far it's CLEAR, we are to use just the natural tiles, NO GLUE......NO GROUT........ETC. The people in beginning of this thread said right away that because of 'the weight of the tiles' nothing is needed to hold them down. There's really nothing hard about this.*** Please read the whole thread..........each and every post on it.*** MFKer's would never want some one to harm their pet fish!