What is calcium?
Calcium is one of the critical building blocks for corals, clams, calcareous algae and many other marine organisms. After sodium and magnesium, calcium is the third-most abundant cation found in seawater and is vital for a balanced marine environment.
Why test for calcium?
Achieving the correct calcium concentration range is critical: too little can lead to poor coral health, while too much can result in depletion of carbonate hardness (KH). Testing for calcium allows you to ensure optimal conditions for your aquarium inhabitants and the stability of other significant water chemistry parameters.
What is the correct level of calcium?
The typical value of calcium found in seawater is 420 mg/l, but values in the aquarium vary from 380 mg/l to 450 mg/l, dependent on the method of running your aquarium.
What to do if the calcium level is wrong?
If the calcium level in your aquarium is wrong, partial water changes using a good quality reef salt is recommend to help re-establish the correct calcium concentration. It is also important to check the magnesium and KH as the three are correlated. If the calcium is incorrect, magnesium and KH are also likely to be wrong.
How to test for calcium?
N.B. To avoid cross-contaminating the titrating reagent (Ca-3), do not return the small quantity of the titrant left in the syringe back into the bottle at the end of the test. After use, clean and dry the syringe, tip and titration vessel with mineral-free water (such as RO water, if available) to ensure the accuracy of subsequent tests.
Q: Why do I run out of 1 reagent before the other(s)? A: We fill our test kit reagent bottles to a minimum amount before they are put through a vigorous QC regime. This means that the vast majority of bottles will in fact be overfilled by varying amounts meaning that the reagents may well run out at different rates but you should be able to carry out at least the number of tests stated on the packaging.
To find out more about water quality and parameters in saltwater aquariums, click here.
For common frequently asked questions, click here.