Thanks - the background is styrofoam (sculpted and covered in tree fern, peat moss, and coco fibre) with some heat shaped PVC piping and rope (also coated in the same mix) to represent vines and branches. Unfortunatelty the plants pretty much hide it completely.WOW! You did a great job with that tank.. it's gorgeous. What type of background and substrate are you using? Any changes from the 6 year build?