Two different ALD probe designs are available. One ALD probe is low-profile and slides easily under the carpet behind or next to your aquarium. The other probe style is a tad larger and is designed to be placed on solid surfaces. This probe is used in combination with the ALD module. The probe is weighted making it perfect for solid surface applications such as tile and wood floors, or inside your aquarium cabinet. This weighted version keeps the detection surfaces solidly positioned for fast detection of leaks.