Feature: 1. The hydrometer is designed to provide temperature‑corrected readings in warm water aquarium, fast, easy, accurate, durable and easy to read. 2. The full scale scale of this sea hydrometer has easy-to-read markings and clearly indicates the safe area. It is small and waterproof and does not require a sensor wire. 3. This sea water hydrometer has an automatic level function, which can automatically identify the level to avoid errors. 4. The aquarium hydrometer is suitable for the detection of brackish water and marine fish tanks. 5. The function of this hydrometer is to test the concentration specifically, which is convenient for professionals to judge the results. Specification: Item Type: Sea Hydrometer.Product Material: Plastic Product Size: Main Body: Longest Part: Approx. 11.2cm / 4.4inWidest Part: Approx. 3.8cm / 1.5inHighest Part: Approx. 15.3cm / 6in Suitable Type: Suitable for brackish water and marine fish tanks. Product Function: Dedicated test concentration Application Method: 1. Insert the hydrometer below 15 cm to prevent pollutants such as oil film from affecting the accuracy of the test. 2. When the water is full (level with the top of the baffle), take out the hydrometer and place it on a level surface. 3. Air bubbles attached to the pointer will cause inaccurate readings. Carefully tap the hydrometer to shake out the attached air bubbles. 4. Get the reading of the hydrometer, the reading of the oceanarium should be between 1.021 and 1.023. The reading in the rock aquarium should be between 1.024 and 1.026.5. Use hydrometer in water with a temperature range of 68-86F (20~30℃). 6. Clean the hydrometer after each use. The remaining salt crystals in the hydrometer will affect its accuracy. Soak the hydrometer in warm water for 30 minutes, then rinse with water to remove salt crystals. Package List: 1 x Hydrometer