The Salifert Calcium Test Kit is an accurate testing kit for saltwater environments. It measures the level of calcium, an important component to the growth of the skeletal structure of various coral species as well as benefiting the biological processes of many other organisms. The ideal level of calcium in a tank should be 400 - 450 mg/l and should never vary more than 15 mg/l. The Salifert Ammonia Test Kit accurately displays changes in the calcium content with accuracy up to 10 mg/l incrementally. The color change will be noticeable and detects small but significant fluctuations within minutes. Kit can perform between 50 - 100 accurate measurements.