Creating and maintaining a thriving marine or reef tank is a delicate balancing act. The triumvirate of calcium, alkalinity, and magnesium plays a pivotal role in ensuring the health and vitality of your coral ecosystem. In this comprehensive guide, we’ll explore the recommended concentrations for these elements and delve into how they intricately influence aragonite formation, a key factor in the structure and growth of coral reefs.  

Aragonite vs Calcite, why do we Prefer Aragonite? 

Aragonite and calcite are almost identical. They’re both calcium carbonate, but they differ in their crystal structure.  

Calcite, being a trigonal structure is naturally more brittle than aragonite, which falls in the orthorhombic family of crystal structures.  

This same phenomenon explains the difference in hardness for graphite in pencils and diamonds. Both are just carbon but bonded differently. Diamond’s structure results in a significantly stronger material than graphite. 

Having strong aragonite foundations means corals have stronger skeletons, helping them stay anchored and healthy. Calcium, alkalinity and magnesium all play a major role in aragonite formation and stability. This is why we use the “CAM” acronym, for Calcium, Alkalinity and Magnesium respectively.  

Understanding Recommended Concentrations: 

Calcium: The recommended calcium concentration typically falls within the range of 405-440 ppm for marine/reef tanks. Calcium is a fundamental building block for coral skeletons, aiding in their growth and overall well-being. 

Alkalinity: The recommended alkalinity concentration typically falls within the range of 7.4-10.5 dKH or 132-188 ppm for marine/reef tanks. Alkalinity acts as a buffer, preventing rapid pH fluctuations and promoting stable conditions for coral life. 

Magnesium: Recommended Concentration: The recommended magnesium concentration typically falls within the range 1,230-1,310 ppm for marine/reef tanks. Magnesium is crucial for the proper formation of calcium carbonate, preventing its precipitation and ensuring a balanced environment for coral growth. 

The Interplay of Calcium, Alkalinity, and Magnesium: 

Calcium and Alkalinity: A Symbiotic Relationship 

Calcium and alkalinity work hand in hand in coral health. Calcium is essential for the construction of coral skeletons, while alkalinity acts as a stabilizing force, preventing rapid pH changes that can stress corals. Striking the right balance between these two elements ensures optimal conditions for coral growth and development. 

Magnesium’s Role in Aragonite Formation 

Aragonite, the crystal form of calcium carbonate, is a primary substance in coral skeletons. Magnesium plays a crucial role in preventing the precipitation of calcium carbonate, allowing aragonite to form in a controlled manner. Maintaining adequate magnesium levels ensures that calcium and carbonate ions are available for aragonite production, promoting strong and resilient coral structures. 

Maintaining Balance for Coral Health: 

Regular Testing and Monitoring: 

Regularly check and monitor calcium, alkalinity, and magnesium levels using reliable test kits or going to your LFS for a more accurate test, whilst also maintaining a stable specific gravity. This practice helps in promptly identifying and addressing any fluctuations, ensuring a stable environment for your corals. 

Supplementation: 

Quantum’s marine salts and Step 3 – Aragonite Enhancers™ supplements are a high quality, easy to use source of CAM elements to help promote strong aragonite foundations.  

Water Changes: 

Regular water changes are an effective way to replenish essential elements and maintain a stable environment. Ensure that the new saltwater mix used for water changes is properly balanced with the necessary calcium, alkalinity, and magnesium levels. 

Conclusion: 

In the intricate world of marine and reef tank keeping, understanding and maintaining the delicate balance of calcium, alkalinity, and magnesium is paramount. These essential elements not only contribute to the overall health of your corals but also play a crucial role in the formation of aragonite, the building block of coral skeletons. By adhering to recommended concentrations and adopting proper maintenance practices, you’ll be well on your way to fostering a thriving and resilient marine ecosystem in your aquarium. 

Invest time in regular testing, supplementation, and water changes, and witness the rewards of a vibrant coral reef that reflects the beauty and complexity of the ocean’s wonders right in your own home. 

Happy reef-keeping! 

Written by Jordan Kambanis - Chemical Engineer BEng, Hons (Chemical & Biomolecular) BSc (Chemistry)