The Pond Guy Muck Defense tablets digest accumulated organic debris also known as pond muck that reside at the bottom of your water garden removing excess nutrients improving water clarity and eliminating noxious odors. Upon application the Muck Defense tablets sink below the surface of the water releasing beneficial bacteria that instantly begin digesting debris. Muck Defense is great at removing hard to reach muck from the bottom of gravel & rock pond bottoms. All the decaying organic material adds to your nutrient load which in time can create algae blooms. Muck Defense reduces the waste and eliminates pond odors to keep your pond clear and balanced.