In natural seawater, boron is a non-conservative major element with a concentration of ~4.54 ppm. Boron plays an active role in regulating the pH in marine systems, and maintaining the boron concentration within a narrow range of the [B]NSW, relative to systems with depressed [B], typically results in faster growth of coralline algae and formation of aragonite in reef-building invertebrates in most systems, when all other physical and chemical requirements are met. Recent experimentation with maintaining slightly elevated [B] in reef aquaria indicates that enhanced production of red phytopigments results, improving color intensity of zooxanthellate corals with a yellow, orange, or red base coloration.
The importance of boron to reef-building organisms is most apparent when beginning to dose it in aquaria with depleted boron concentrations, and/or in which the sea salt mixture employed is boron-deficient; in such cases, changes in the rate of coralline algae growth, as well as in the appearance of many corals, may be observed within the first weeks of daily dosing. Maintaining boron within a range of 4 - 6 ppm is sufficient for long-term health, growth, and coloration of corals when all other physical and chemical requirements are met. The rate at which boron is extracted from the water is determined by the stocking density of boron-depleting livestock, rate of production of weak acids that may impact alkalinity and pH, composition of buffer(s) employed in the system, characteristics of lighting and method(s) of filtration employed, and other biological, physical, and chemical conditions; therefore, each aquarium will have different requirements for the rate of boron supplementation. Once the rate of boron uptake in the aquarium has been determined (see opposite), the proper dosing rate of this supplement can be easily calculated. It is recommended that a quality salt mix with the proper (not augmented) alkalinity and concentrations of major, minor, and trace elements be used to establish natural seawater parameters in marine aquaria, providing a stable ionic foundation on which to build.