Refugium mud, or miracle mud, offers many benefits for a saltwater aquarium. Mud is a great breeding ground for beneficial organisms like copepods that eat waste and serve as fish food. Refugium mud has anaerobic zones for reducing nitrates in the aquarium, which reduces algae and promotes fish health. Speaking of fish health, refugium mud releases trace elements and minerals, which are great for both fish and corals. Refugium mud can help prevent head and lateral line erosion, also known as HLLE or hole in the head disease, which affects some fish in captivity.