Salt Mixes & Hydrometers

Creating artificial sea water for a marine aquarium requires aquarium salt to be added to fresh water either purified RO or DI water, or just conditioned tap water. Fish tank salt is manufactured by several companies, and each company manufactures its salt for specific purposes. Some salt is designed for reefs, while others are simply designed for fish only aquariums. In order to read the concentration of salt after mixing it, a hydrometer or a refractometer are used. The hydrometer will either be a floating type or an external type while the refractometer is external and will use optics.