I have them in tubs on a rack, under each tub there are two lengths of heat cord around 10cm apart, the substrate is washed sand, the sand at the cold end is kept moist, there is a glazed terracotta dish with a chip out of it at the cold end, the geckos will back fill this dish with moist sand. No water bowls are ever supplied but the sand is ALWAYS kept moist, the sand at the hot end is always bone dry and heated for 8 - 10 daylight hours. In the wild levis dig deep burrows into moist cool earth, in the warmer months they come to the dry warm surface to feed, by keeping them this way is is about as close as you will get in a two foot tub to meet their needs.