Studies have shown that about 60% of the weight of calcium carbonate secreted by the epithelial layer of corals is carbonate, highlighting the importance of these elements in calcification. Additionally, carbonate, bicarbonate, and boron play a crucial role in maintaining the hardness and stability of pH in seawater. Without these three elements, and with their reduction, calcification becomes impossible, and the water tends toward acidity.

Maintaining water hardness in the range of 7 to 11 dKh (depending on the needs of corals and living organisms in the ecosystem) and stabilizing pH between 8.1 and 8.4 helps sustain the chemical conditions of the water, promoting growth and development in corals alongside the biological forms of calcium and magnesium.

One of the most important parameters in a coral aquarium is maintaining and stabilizing the water hardness in the tank. The less fluctuation in water hardness we can achieve daily, the more we will witness growth and coloration in corals. The standard seawater hardness is between 7 to 9 dKh, with suggested ranges for LPS coral aquariums being 8 to 10, full SPS aquariums being 7 to 8, mixed LPS and SPS aquariums being 8 to 8.5, and fish-only tanks being 8 to 11.

This test kit allows you to read the hardness value with maximum accuracy and high resolution in the shortest time possible.

Using the large syringe included in the kit, add 4 cc of aquarium water into the test vial. (For more tests, you can use 2 cc of water in the vial.)

Add 4 drops of solution number 1 to the test vial and shake for 5 seconds. (If you used 2 cc of water in the first step, add 2 drops of solution number 1.)

Using the small syringe, after attaching the needle, draw 1 cc of solution number 2. (There is no need to remove air bubbles from the syringe; the air volume is accounted for in the test calculations.)

Begin injecting slowly while gently shaking the test vial until the color of the test solution changes from blue to yellow. Then read the remaining solution in the syringe and refer to the numbers in the kit’s table to determine the aquarium water hardness. (If you used 2 cc of water in the first step, multiply the remaining amount in the syringe by 2, then refer to the table on the back page.)

If the hardness is too high or too low, it can lead to coral death and the separation of soft tissue from the hard tissue in corals, causing them to whiten. Therefore, knowing this measurement is essential for aquarists to assess and take necessary actions. If the aquarium water hardness is low, you can use DeepOcean Alkaline Buffer 8.4 powdered or liquid supplements for optimal adjustment. If the hardness is high, performing a siphon of part of the tank water with DeepOcean salt can restore the water hardness to acceptable levels.

a) After use, be sure to rinse the test vial with R/O or distilled water and allow it to dry. Due to hardness in city water and its residue on glass, it is preferable not to use it for rinsing.

b) Store the test kit out of reach of children and at room temperature.

c) In case of contact with skin or eyes, rinse thoroughly with water.