Calcium (Ca2+) is vital to many biological functions. In saltwater aquariums, calcium should remain in the proper ionic balance along with alkalinity (KH) and magnesium (Mg2+). A calcium level outside of this ionic balance can cause poor coral skeleton growth and tissue necrosis. Calcium uptake in reef aquariums can change over time and should be regularly tested to ensure proper dosing.

Though more closely maintained in saltwater systems, freshwater aquariums also require routine monitoring of calcium. Plants require calcium for proper leaf growth and other functions. Invertebrates, such as shrimp and snails, require the right amount of calcium to maintain shell integrity and prevent molting problems.

Tropical community fish: 75+ ppm calcium
African cichlids: 120+ ppm calcium
Marine aquariums: 300 to 400 ppm calcium
Reef aquariums: 400 to 450 ppm calcium

To remove childproof safety cap, push down while turning.

1. Fill a test tube with 5 ml of water to be tested (to the line on the tube).
2. Add 10 drops from Calcium Test Solution Bottle #1, holding dropper bottle upside down in a completely vertical position to ensure uniformity of drops added to the water sample.
3. Cap the test tube and gently shake several times to mix solution. Attention! Always use the cap. Avoid skin contact as this may affect the test results.
4. Vigorously shake the Calcium Test Solution Bottle #2 for at least 10 seconds.
5. Holding the bottle vertically, Add Calcium Test Solution #2 drop by drop into the test tube , shaking gently between and counting drops. Stop when the solution changes from pink to blue. As the blue endpoint is approached, color will change from pink to purple before changing to blue. After purple color forms, only 1-2 more drops should be required to reach the blue endpoint. Calcium level is # of drops x 20. Use chart to determine calcium level.

To decrease calcium, perform partial water changes with lower calcium content water.

To increase calcium, add a calcium supplement like Fritz Rift Lake Cichlid Salt, or Fritz RPM Elements Calcium Buffer System Part Two.