How to Use Hydrometers in Aquariums
- 1). Condition your new swing-arm hydrometer by soaking it in the salt water from your marine aquarium. Soak the hydrometer for one day prior to use.
- 2). Dip the hydrometer slowly into the aquarium after the proper amount of conditioning. Ensure that the bottom fill port is below the water's surface. Wait while the water flows upward into the hydrometer and over the weir, the lip which allows the body of the hydrometer to fill with water.
- 3). Lift the hydrometer up to eye level and tap the acrylic box gently to dislodge any air bubbles that are attached to the pointer. Numerous air bubbles on the pointer will give an inaccurate result.
- 4). Place the hydrometer on a level work surface and read the salinity and specific gravity scales. You can chose which scale you prefer to work with. The salinity scale will be marked in parts per thousand. Many swing-arm hydrometers have a color blocked "safe zone" printed on the acrylic box and are accurate to a specific gravity of approximately 0.001.
- 5). Discard the sea water after testing and rinse your hydrometer thoroughly in freshwater. It is important to rinse the hydrometer in order to flush away deposits of salt; these deposits can interfere with your future readings.
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