Directions: Spread the substrate evenly over the bottom of the enclosure to a depth of at least 1-2"(2.5-5cm). Spot-clean daily and completely replace every two or three weeks, or more frequently if it becomes heavily soiled or wet. If you are using an under-tank heatmat as your heat source do not use a thick layer of Aspen as this may cause the heat mat to overheat. Please refer to the heatmat manufacturer's instructions for more information.