The 4 ounce container of Aqueon Shrimp Essentials helps to replace the critically important trace minerals vital to the survival of invertebrates such as shrimp and crayfish. These trace elements are often removed through chemical filtration as well as by the individual shrimp within the aquarium. Freshwater invertebrates have durable exoskeletons and require additional nutrients to contribute and encourage important biological processes such as molting and osmoregulation. These essential nutrients help the crustaceans rid themselves of their old exoskeleton and develop and harden a brand-new one. Ideal for use when changing water, adding fish or for disinfecting tap water. For a brief period of time, it is recommended to remove any chemical filtration when dosing, including carbon or other resins, to prevent absorption and optimize the available nutrients for your aquatic pets.