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API Calcium Saltwater Aquarium Test Kit

API  |  SKU: X560801


This kit allows for easy and accurate measuring of calcium levels to help in maintaining a healthy aquarium.



  • Contains 1 API Calcium Test Kit Saltwater Aquarium Water and includes 2 bottles of testing solution and 1 glass test tube with a cap.
  • Easy and accurate—simply compare your results with the color chart and follow the included recommendations.
  • Corals, crustaceans, mollusks and some types of encrusting algae need calcium for skeletal growth.
  • This kit uses the titration method to measure calcium levels as low as 20 mg/L.
  • For use in saltwater aquariums only.


Why test for Calcium?
Monitoring calcium levels is essential for keeping a successful reef aquarium. Reef organisms use calcium to build a calcium carbonate skeleton. Over time, as the calcium in the water is utilized, the calcium level will gradually drop. Calcium must be present for corals to grow. Even reef invertebrates such as crustaceans, mollusks, and encrusting algae, require calcium to grow and remain healthy.

Calcium levels drop as it is used by invertebrates or as it reacts with excess phosphate. Making a partial water change may help to maintain proper calcium levels, depending on the brand of salt mix. Special calcium additives are also available. Elevated phosphate precipitates calcium, rendering it unavailable to reef organisms. Phosphate enters the aquarium from tap water and is a byproduct of fish and invertebrate metabolism. Use Aquarium Pharmaceuticals Phosphate Test Kit to test for phosphate. If necessary, use Aquarium Pharmaceuticals Phos-Zorb™ to remove excess phosphate. Phos-Zorb is a special phosphate-removing filtration media that comes in a flow-through pouch. It conveniently fits into any filter.

Carbonate hardness (KH), often referred to as alkalinity, is important for reef organisms. As carbonate levels drop the pH becomes unstable. The carbonate hardness level (KH) should be 7-10 dKH [125 – 179 mg/L (ppm)] to encourage growth in a reef aquarium and maintain pH. Use the Aquarium Pharmaceuticals KH Test Kit to measure the carbonate hardness. Add Proper pH 8.2 to increase carbonate hardness and stabilize the pH to 8.2.


Do I need to test calcium parameters in a freshwater aquarium?

No – calcium levels need to be monitored and maintained in reef or marine aquariums, as improper levels can be harmful to corals and crustaceans.


How often should I test my calcium levels?

For best results, test calcium levels with API CALCIUM TEST KIT in your saltwater tank weekly.

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