I didnt use any glue, epoxy, rods, zipties or anything. I just stacked it like a puzzle right on the glass bottom of the tank. I have numorus columns and arches too. Ive never had anything fall, sink, settle, anything. Im getting ready to re do my stack and Im sure Ill sue some epoxy in a few places, but all and all Im just gonna puzzle it together. Makes it alot easier if you dont like the ifnal product.