 Aquarium Hydrometers are an essential piece of equipment for all Marine and Reef Aquariums. The aquarium hydrometer allow you to quickly and easily establish the specific gravity or salinity of your water in the marine aquarium. The aquariums salt concentration is an important factor in keeping healthy livestock.
Marine Aquarium Hydrometers range from the very accurate Aquamedic Refractometer and the Underworld sea test Hydrometer to the Hobby floating Hydrometer. Salt testing Hydrometers are also available with thermometers if needed. A majority of Marine life will be happy in a salinity of 1.021 to 1.023 these numbers being the min and max fluctuations safely occurable for marine aquariums. | 
