If water level below the green indicator means more fresh water is required It is recommended that the proportion of seawater in the seafood pond is between 1.020-1.023, which is within the safety line Placed in any corner of the aquarium, suspended design, automatic temperature/specific gravity test If water level above the green indicator means more salt water is required Green indicators are ideal range of water temperature and specific gravity for most salt water / marine . Test range 0-40℃ 1.000-1.060