Sharon Ram

Sharon Ram

Red Sea's Chief scientist

The importance of Foundation Elements in reef aquariums

Foundation Elements | Red Sea Insights


Achieving a successful coral reef aquarium is dependent upon maintaining stable water parameters that apply to the levels of the major, minor, and trace elements required by the corals. 

Although many elements have an important role in maintaining the desired water parameters, a few of them have a very significant role in the overall stability of the reef aquarium. These elements are the ‘foundation’ of the reef environment, and they include the three major elements: calcium (Ca⁺²), magnesium (Mg⁺²) and bi-carbonates (HCO₃⁻²). These 3 elements have a major effect on the water chemistry (pH stability, alkalinity, seawater ionic strength) and on many of the corals’ biological processes (skeleton formation, ion exchange & photosynthesis).


Corals build their skeletons through a unique process called skeletogenesis. In this process, a layer of special cells in the corals’ soft tissue transports, secretes and concentrates the 3 foundation elements (calcium, magnesium, bicarbonate) and other elements (strontium and barium) into special areas called the “calcifying centers” where a matrix of calcium carbonate (aragonite) is formed.

The process is very complex, with several pathways for ion transportation both from the water column into the calcification centers, and in the opposite direction. Some of the pathways provide passive diffusion through the cell membranes, while other processes require more active and energetic methods such as active diffusion by membrane “pumps” and carrier proteins, which demand a lot of energy from the coral. 

Constant exchange of ions enables the process of skeletogenesis, and without it, corals cannot create stable, healthy skeletons. In the calcification centers, the bicarbonate and calcium precipitate as calcium carbonate (CaCO3 – aragonite). During the process, many protons (H⁺) are released and are pumped back into the coral cells, creating a continuous high pH of 9.8 – 10.3. This high pH enhances the precipitation of CaCO3, and without this high pH level, the coral skeleton will start to dissolve.


How does Red Sea’s Reef Foundation Program support coral skeletogenesis?

On the natural reef, the elements that create the conditions for coral growth, health, and color are always available thanks to a virtually limitless reservoir. In a reef aquarium, however, these elements are quickly depleted and become the limiting factor for coral growth. 

If these elements are not monitored and replenished regularly, they drop to levels which may become lethal for corals. That’s why monitoring and adjusting the levels of the Foundation Elements is essential in order to provide the water conditions required to enable stable, strong and accelerated coral growth rates or to enhance coloration. 

Red Sea’s Foundation Program provides a complete solution for maintaining and replenishing the foundation building blocks of the reef aquarium by providing complete and balanced supplements formulated to work together for long-term use and without changing the ionic balance of the water.

Learn more about Reef Foundation program products >>

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