• Contains calcium, strontium, and magnesium in the same ionic
  ratios found in aragonite. This unique feature increases the
  usefulness of Kalk+2 to reef-building invertebrates such as corals, clams, calcareous algae, etc.
• Provides temporary alkalinity and helps maintain pH within the
  desired range when used as directed.
• Adds no conservative elements, such as chloride, to the
  aquarium.
• Improves upon the industry-standard powdered calcium
  supplement over the past three decades.
• Formulated by a marine scientist.

Calcium, magnesium, and strontium are required for the formation of aragonite, the skeletal material of reef-building invertebrates such as corals, clams, tube worms, and their respective allies. Brightwell Aquatics Kalk+2 provides these elements and may also be used to help regulate pH in reef aquaria. Kalk+2 does not contain chloride salts, which is a strong point for some hobbyists. The use of kalkwasser-type products remains very popular with many seasoned hobbyists, regardless of innovations in calcium-delivery methods.

Kalk+2 is intended for use by experienced hobbyists who are familiar with kalkwasser (calcium hydroxide-based) products. The calcium concentration and pH in the aquarium should be determined by using an accurate test kit prior to supplementing. Do not add this product directly to an aquarium without diluting in water as directed, and do not overdose; it must be added in a controlled fashion with a dosing device.

Create a stock solution by dissolving 6 grams (~1 tsp) of Kalk+2 in 1 US-gallon of fresh water (preferably purified) and allowing at least one hour for any settling to occur; each ml of the saturated solution will increase the [Ca2+] in 1 US-gallon (3.785 L) of water by 2.3 ppm, strontium concentration by 0.04 ppm, and magnesium concentration by 0.06 ppm. This solution must then be dosed/dripped into the aquarium at such a rate that salinity does not fall below 1.021 g/cm3 and pH does not increase by more than 0.1 every hour, nor is it ever allowed to exceed a value of 8.5.

Dosing at night when pH in a reef aquarium is naturally depressed is often performed to avoid exceeding the maximum allowable pH value. If the [Ca2+] in an aquarium is gradually dropping despite using this product as directed, the rate of evaporation may be insufficient or pH may be too high to dose sufficient calcium to compensate for the rate of removal by reef-building aquarium inhabitants and/or undesirable chemical reactions. In this case, a secondary calcium supplement may be needed to occasionally re-establish the natural seawater concentration of calcium in the aquarium.