Salifert Calcium Profi-Test Kit

Calcium is a core building block for calcareous algae, hard coral skeletons, and the skeletal needles of soft/leather corals. Natural seawater holds 400-450 mg/L, and a stable reef tank should stay within about ±15 mg/L of that range - so an accurate test matters as much as a good additive. Resolution: 10 mg/L steps, with a sharp, easy-to-read color change Kit size: approximately 50-100 measurements Low calcium slows coral and calcareous algae growth, so regular testing lets you catch depletion before it becomes visible in slowed growth. Pairs well with a properly balanced calcium additive - poorly formulated ones (straight calcium chloride, or excess kalkwasser) can throw off the broader ionic balance of the tank.