About Aquarium Hydrometers & Salinity Testing
It is commonly known that the ocean is composed of saltwater, but the level of salinity is an important factor in aquarium maintenance. The standard salinity for seawater in its most natural state is 35 ppt. In order to measure the salinity of the ocean or your aquarium, you must weigh the water, then evaporate all the liquid, and measure the weight of the salt mix that remains. Or, you can save yourself the trouble and do a salinity test.