Calcium is one of the most important elements for thriving reef aquariums. A steady supply of biologically available calcium is required to ensure healthy coral growth. Closed systems like home reef aquariums will eventually exhaust their supply of calcium without regular supplementation. Calcium additives are, therefore, necessary to ensure proper calcium levels. However, calcium supplementation is more than simply dispensing an additive. Avoid common mistakes and learn how to optimize calcium supplementation.
Calcium availability in nature
But more importantly, the chemical composition of seawater tends to be stable and is not commonly subject to dramatic fluctuations. In other words, the supply of natural calcium is consistent and always present for corals.
In contrast, artificial environments such as home reef aquariums are subject to change. In heavily stocked reef aquariums, calcium is actively utilized and calcium levels rapidly decline. Also, as corals grow, they remove carbonate ions and combine them with calcium ions to form their hard skeletons. Without supplementation, not only will corals experience a reduction in growth but the aquarium system may also experience a reduction in buffering capacity and pH.
Supplementing calcium in reef aquariums
There are factors that limit or restrict this approach towards calcium supplementation. The fundamental factor is that aquarium water is only capable of keeping a finite amount of dissolved calcium in solution. If this concentration exceeds the water's capacity to keep it in solution, then dissolved calcium falls out of solution in the form of calcium carbonate. In certain cases, the calcium carbonate precipitate can make an aquarium appear as if it is snowing. While the "add more at once" approach is clearly not the appropriate way, following a static formula of "X" amount of calcium additive per month may not be the best approach either. The calcium demand of a reef aquarium changes as it matures and supplementation needs to be adjusted accordingly.
Calcium & alkalinity
Determine calcium need
Simplify calcium supplementation
Keep calcium supplementation simple by using balanced formulas for maintaining both calcium and alkalinity. These two part formulations, like Two Little Fishies C-Balance, are capable of maintaining both high calcium levels and alkalinity without causing a buildup of unwanted compounds. This method of maintaining calcium and alkalinity in reef aquariums has become very popular due to their ease of use.
In addition, be sure to test magnesium levels. Magnesium plays an important role in maintaining the correct balance between calcium and alkalinity in seawater. It helps stabilize alkalinity and calcium levels by preventing excess precipitation of calcium and bicarbonate. Fortunately, maintaining proper magnesium levels between 1,250 and 1,350 ppm is as easy as performing regular water changes with a quality saltwater mix.