If and when you experience a hard time at maintaining your calcium and alkalinity levels, test your magnesium level to see if it's between 1250 ppm and 1350 ppm, which are natural seawater levels. A low magnesium level at or less then 800 ppm will cause your calcium and alkalinity levels to become unstable and stress your entire livestock in your aquarium.

Saltwater Correct Concentrated Calcium is a supplement designed to be used as part of a 2 part Calcium & Alkalinity supplement system or to use alone to raise your calcium values. Monitoring and maintaining your calcium values is part of helping to stabilize your water chemistry values, and you will see better coralline algae growth, coral growth and invert growth. Directions for dry form: Start out by adding 1 teaspoon per 50 gallons of tank water. You should not exceed 30 ppm daily. It’s recommended to take your dosage and dilute in some R/O DI filtered water and add slowly into sump or if no sump, use half dose at a time and pour in front of a strong water flow. Take extreme care not to add this product too quickly, will cause some corals to shrink-up. Drip method is best. Directions are just a guide line. Wait 24 hours and retest. Adjust dosage up or down. Add daily to reach your desired calcium level, then as part of a daily or weekly regimen to maintain your calcium values. Ideal calcium values are 380 ppm to 450 ppm. If you are have difficulty maintaining your calcium values, check your magnesium, alkalinity and borate values and adjust to their proper values in order to maintain a well balanced saltwater aquarium system.   Contents: Calcium Chloride, Purity: (Min) 94% (Max) 97%