Sachem coral Crete is two-part epoxy putty that can be used to secure coral to rockwork or to fuse together rockwork for more stable foundations in reef aquaria. It has a working time of 5 minutes which allows for plenty of work time while also quickly securing coral or rock. Coral Crete is ideal for working with larger colonies of branching coral, most large polyp coral or adhering plating coral to rockwork. Coral Crete is safe for aquarium inhabitants when used as directed.