Here's a couple of pics of my diy sand background that I've made up for a 5gal tank. I still have to stick a couple of thin bits of wood to it yet so it's not the final product. (that's why there are patches without sand) All I did was cut a piece of plywood to the size I needed, worked out where I want to hot glue the bits of wood & put a little making tape over those spots. I put a thick layer of polyurethane varnish over the wood, removed the making tape & then covered the whole thing with sand I dug up from my backyard. Let it dry for 24hrs & then slipped it in behind the tank. It's just held in place with a couple of pieces of duct tape. I'm not real happy with the finish this sand has given me but the general concept seems to work. I'm starting on a couple other designs that 'm going to trial as well with a darker, coarser sand & another one that uses fake plants, river pebbles & bits of wood.