When talking about salinity, beginners often think only in term of the dissolved salts in the saltwater aquarium. However, it is important to know that salinity only gives you the value of the total amount of dissolved material in the water. It does not tell you the detail or the breakdown of the dissolved material or elements in the water. This means that you still need to monitor the other important element individually. Salinity in the saltwater aquarium needs to be monitored periodically as fluctuation in is value tends to stress the fishes and invertebrates which can be fatal in the long run. Due to the evaporation process of the saltwater, which cause the water to be lost while leaving all the minerals and solids behind, salinity value tends to increase over time. As such, regular monitoring and topping up of the tank with fresh and pure water is needed to ensure that the level is within the control. Visit this page for more information about salinity and how to control it in the saltwater reef aquarium.