Salinity Refractometer FULLY EQUIPPED with ATC Versatile swing-arm hydrometer accurately measures both specific gravity and water temperature.
Its clever design allows periodic or continuous reading of the most important water quality parameter in saltwater aquariums.
You can measure from 1.010 to 1.030 specific gravity and 64-97?F. The Hydrometer provides:- Measurement of specific gravity (degree of salinity) in a saltwater aquarium
- A patented design which enables the device to be permanently installed inside the aquarium for continuous, real-time reading of salinity in addition to regular periodic reading
- Built-in digital thermometer, ensuring the water that is being tested is at the correct temperature
Specification:Measure from 1.010 to 1.030 specific gravity and 18-36?C (64-97?F). Hydrometers, Salinity, Specific Gravity, & TemperatureThe most basic water quality parameter in a saltwater aquarium is the salinity. Salinity is a theoretical measure of the amount of salt contained within a volume of water, normally expressed as grams per liter (g/l) or parts per thousand (ppt).
(Note: salinity should not be confused with manufacturer's instructions for the preparation of artificial seawater expressed in g/l or lb/gal.) Unfortunately, it is not possible to measure salinity directly. However, it has a temperature-dependent relationship with specific gravity (S.G.), which is easily measured with a hydrometer.
For a particular salinity, S.G. increases with decreasing water temperature and, therefore, a S.G. measurement is only meaningful if the temperature is also known. Conversion of S.G. to salinity is done at a constant temperature of 25?C/77?F.
Convertion of S.G. to Salinity at a constant temperature of 25?C/77?F: S.G. at 25?C/77?F | Salinity | 1.018 | 26.9 | 1.019 | 27.8 | 1.020 | 28.7 | 1.021 | 30.6 | 1.022 | 31.5 | 1.023 | 33.4 | 1.024 | 34.3 | 1.025 | 36.2 | 1.026 | 37.1 |
Effect of temperature on S.G. for a constant Salinity of 30.6 ppt: Water temperature | S.G @ Salinity of 30.6 ppt | ?C | ?F | 7 | 44.6 | 1.025 | 13 | 55.4 | 1.024 | 18 | 64.4 | 1.023 | 22 | 71.6 | 1.022 | 25 | 77.0 | 1.021 | 28 | 82.4 | 1.020 | 31 | 87.8 | 1.019 | 34 | 93.2 | 1.018 | 37 | 98.6 | 1.017 |
Salinity in the Saltwater Aquarium It is essential to maintain correct salinity in a saltwater aquarium because of the fine balance between the concentrations of salts in a fish's body tissue, compared with that of the surrounding water. The ability of fish to control small fluctuations of these concentrations in nature is called osmoregulation. However, if the salinity of the water in an aquarium is outside the range of naturally occurring salinities, then fish and invertebrates will experience osmotic stress, which can lead to their death.
The most common occurrence of salinity variation is the gradual increase in salinity due to evaporation. Constant and accurate measurements of S.G. are, therefore, essential to ensure correct conditions. A salinity of 30.6 ppt (i.e. a specific gravity of 1.021 at 25?C/77?F) is recommended for most saltwater aquariums. | 
