Easy to use. Measure both Temperature and Specific of the water. Green indicators are for IDEAL of water temperature and specific for most salt water marine aquariums.
Instruction: Place the hydrometer into water, and let it flow freely in the water - If water level is below the green this means more FRESH water is required - If the water level is above the green this means more salt is required.
Specifications: Material: - Glass Colour: As the picture shows Size: 20cm/7.87
