Blue Marine Refractometer

The Blue Marine refractometer is especially designed for measuring the salinity of natural seawater in marine aquaria and not for measuring only the level of sodium chloride as many other refractometers falsely do. The Blue Marine refractometer is equipped with automatic temperature compensation, meaning the meter will work correctly at normal ambient room temperatures. Calibration is essential for correct measurements and should be done regularly.

Important

• Ensure that the glass prism and cover are clean before use and no salt residues are present.
• Clean and dry the refractometer directly after use. Be sure that no salt water is left as this will leave salt crystals, which will strongly infl uence future readings.
• Prevent the refractometer from strong shocks as this can damage the meter. Hence, store the meter in its box when not using.

Calibration

Calibration should be done at a room temperature of 20°C in the following 3 steps:

1 Flush the pipette several times with RO water (Reverse Osmosis) and then cover the blue coloured prism completely with RO water, while holding the refractometer horizontally. Let excess water drip of.

2 Close the cover onto the RO water and make sure that no air is captured under the cover. After 10 seconds look through the eyepiece while pointing at a bright light source. Focus by turning the eyepiece.

3 The transition line between blue (above) and white (bottom) should be on the zero mark at the bottom. Adjust if necessary with the included screw driver. The adjustment screw is protected by a plastic cap which should be temporarily removed before adjusting. Now, calibration is completed.

Measuring

Measuring is easy and quickly done in the following 3 steps.

1 Flush the pipette several times with water from your aquarium and then cover the blue coloured prism completely with the water sample from your aquarium, while holding the refractometer horizontally. Let excess water drip of.

2 Close the cover onto the water and make sure that no air is captured under the cover. After 10 seconds look through the eyepiece while pointing at a bright light source. Focus your view by turning the eyepiece.

3 The transition line between blue (above) and white (bottom) displays the salinity/specifi c gravity of the water from your aquarium.