What is a Hydrometer and why do I need one?
Hydrometers measure the salinity in an aquarium by measuring the specific gravity. Specific gravity is defined as the ration of the weight of one liter of seawater to that of one liter of pure water at a specified temperature. Most standard hydrometers will give a fairly accurate reading, with some having an inaccuracy ratio off by .01 or .02 of a degree. Refractometers are longer lasting and a more wise choice for your investment, and offer a more accurate reading. Refractometers are an instrument that refracts light through the water to give you a measure of salinity. Either a Hydrometer or Refractometer is a necessary tool needed in conjunction with other water quality control devices to aid in keeping proper water parameters. We carry the Milwaukee Refractometers professional grade also the Red Sea Hydrometer-Thermometer, Deep Six Hydrometer, and the Sea-Test Hydrometer.
