The importance of Foundation Elements in reef aquariums
Red Sea's Reef Foundation program
// Published: 26.02.2014


The importance of Foundation Elements in reef aquariums

red sea reef Foundation program-elements- Foundation-Blog-Sharon

Achieving a successful coral reef aquarium is dependent upon maintaining stable water parameters at the levels of 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, sea water 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 are passive, such as those which provide passive diffusion through the cells 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?

In the natural reef the elements which create the conditions for coral growth, health, color are available in a virtually limitless reservoir. However in a reef aquarium these elements are quickly depleted and become the limiting factor for coral growth. If not monitored and replenished regularly they drop to levels which may become lethal for corals. Thus, 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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Red Sea’s Reef Foundation A

Foundation A contains concentrated and balanced calcium, strontium and barium. All 3 elements are essential for the production of aragonite coral skeletons, with Ca as the major element utilized for binding bicarbonate, and Sr and Ba acting as substitute elements that can be found in deeper and older parts of the skeleton.




Strontium and barium have 2 significant roles:

  1. Substitutes for calcium – Corals transport calcium to newer calcification centers from skeleton deposits and replace Ca with Sr and Ba.
  2. Enhancing the production of strong aragonite skeleton instead of weaker calcite form of CaCO3.

Red Sea’s research shows that keeping these elements in the exact balanced proportion is essential for their activity, as they can only penetrate soft tissue by specific Ca/Sr/ Ba channels and transporting proteins, and therefore any imbalanced concentration may interfere with their biological activity.   Therefore Foundation A is formulated with all these elements together in the exact proportion required in order to keep proper Ca:Sr:Ba concentration in the water and in the coral skeleton. Furthermore, the research showed that the consumption of Sr & Ba is related to the consumption of Ca, enabling the safe replenishment of these 2 essential elements by accurately measuring and dosing of calcium.(with no need to test Sr & Ba levels).  Learn more about Reef Foundation A >>


Red Sea’s Reef Foundation B

Foundation B replenishes bicarbonate and carbonates in the water. Using Reef Foundation B will enhance the carbonate alkalinity that is essential for calcification and maintaining high pH in the calcification center. It is important to replenish the carbonate alkalinity rather than total alkalinity, as total alkalinity is influenced by borates, sulfates and phosphates.  Learn more about Reef Foundation B >>

Red Sea’s Reef Foundation C

Foundation C replenishes Mg in the water. Mg is one of the major ions in sea water and although it only represents a small % of the coral skeleton (1-3%) it has critical role in enhancing the formation of aragonite rather than calcite. Incorrect Ca:Mg proportions lead to the formation of weak and brittle calcite coral skeletons. Mg has also important role in maintaining stable carbonate alkalinity by controlling and inhibiting the spontaneous precipitation of CaCO3 in the water, through the availability of a reservoir of MgCO3.   Implementing Red Sea’s Reef Foundation Program will maintain the required concentration of Foundation Elements; providing optimal conditions for enhancing coral calcification rates through increasing passive diffusion, while reducing the energetic demands on the coral caused by the need to pump the elements into the calcification centers.  Learn more about Reef Foundation C >>


The end result is  stronger, healthier and more colorful corals.