Immerse the hydrometer into the salt water aquatic tank slowly, read the reading inside or outside the tank at eye level.
If there is is any air bubble on the indicator, use the plastic stick attached and stir the air bubble away.
The outside range of scale indicates salinity in ppt, the inside range of scale indicates specific gravity.
The suitable range is suggested to be between 1.020 – 1.023 under temperature of 25°C.
After the hydrometer has been used, it should be cleaned with tap water, if any salt particles stick on the indicator, soaking the hydrometer in warm water for 30 minute and then rinse with tap water again.