Calcium supply
at least in stony coral tanks - a basic prerequisite for success.
But even in tanks with soft and leather corals, the proper Ca content helps to stabilize the environment and maintain consistent pH values.
There are many different ways to add calcium: calcium reactor, calcium hydroxide mixer, calcium addition according to Balling, and various ready-made products in liquid or solid form.
All of them can be used, although the size of the pool must be taken into consideration.
A) The Calcium Reactor. In my opinion, the commonly used calcium reactor is the simplest type in terms of workload. Once filled and properly adjusted, with a pH controller and solenoid valve, it operates until the CO2 cylinder is empty. Filled with coarse coral rubble, it supplies the tank with sufficient and even water.
As an alternative to coral rubble, artificial granules can also be used, but coral rubble is unsurpassed in its solubility. It is alleged that, depending on its origin, it contains more or less PO4, thus leading to the introduction of phosphates.
However, we have not yet been able to establish any connection between algal infestations and the use of coral rubble in the reactor.
On the contrary, a PO4 deficiency can occur in heavily overgrown aquariums with a small fish population. The small input from the calcium reactor can be an important supplement to the rapidly depleted PO4 in these tanks.
We use the calcium reactor on the farm with coral rubble and MG-Pro. B) The calcium hydroxide mixer is useful and the first option for calcium supply (already used with calcium hydroxide in the 1980s by Peter Wilkens, one of the pioneers of coral keeping). Here, however, it comes in the form of a water canister with a few tablespoons of calcium hydroxide for mixing and adding the clear, limed water after the settling phase.
The same principle is used in the lime mixer, albeit in a more labor-saving version. The lime water has the side effect of precipitating PO4, thus helping to prevent phosphate buildup. The precipitated phosphate accumulates, at least in part, in the decoration and is said to be a precursor to filamentous algae infestations.
We'd like to note that we've also observed filamentous algae infestations in tanks without the addition of lime water. We use the lime mixer to refill evaporated water and simultaneously rescale and precipitate phosphate. However, we only fill it with calcium hydroxide once a week. It's used up after 2-3 days at the latest. After that, we only pump water through the fully cured lime substrate until the next calcium hydroxide addition.
C)....according to Balling...invented by Hans-Werner Balling. Calcium chloride and sodium bicarbonate in the correct ratio are added to the water, usually daily, and are also a very effective way of adding calcium.
NaCl-free sea salt is used to balance trace elements.
Handling the necessary storage containers and regularly remixing the solution is somewhat cumbersome. However, dosing can be easily adjusted using appropriate pumps, thus maintaining consistent water quality.
Various trace elements can be added to the individual solutions.
For calculations, also look at various "salt/balling calculators" on the Internet.
A more advanced method is Balling Light® according to Fauna Marin, which we also partially use on the farm. Here, mineral salt is omitted and the mineral intake is controlled by a balanced addition of trace elements.
D) Finished products This leaves the finished products of various companies, which are all quite expensive and are only useful in small pools for cost-effective use.