Aquarium Refractometer

In order to measure the salinity (salt content) and gravity of your aquarium's water, you need to use an aquarium refractometer. These instruments can be purchased for around $30 to $70 dollars and are found in pet stores and via online retailers. Hydrometers can be inaccurate and hard to read over time. Refractometers are affordable, easy to use, and highly accurate. Most come with an adjustable eyepiece, carrying case, and screwdriver for simple calibration. They have to be tested and calibrated prior to shipping, so they are ready to be used out of the box. Even at very low salt levels, aquarium refractometers can give accurate readings. Why is this important? Well, sensitive tropical fish require very specific environments and one of these instruments can help you maintain the proper aquatic balance. To use an aquarium refractometer, you put one or two drops of your tank's water onto the prism glass and close the plate cover over the glass. The light that passes through the glass will slowly bend and show through onto an internal scale. The scale is then magnified through an eyepiece that lets you read the water's measurements. On the scale, there is a blue top portion and a white bottom portion. Where your colors intersect is your reading. One side will measure the salinity in your water while the other measures gravity. Consider your fish's specific needs when determining where the reading should be for your aquatic environment.