JBL ProAqua Mg-Ca test kit (Measures Magnesium / Calcium In Saltwater)

Description

The JBL ProAqua Test MgCa Magnesium/Calcium is an easy to use drop test to measure the magnesium and calcium content of saltwater. As the magnesium content can only be measured by recording the sum of magnesium plus calcium, the two tests have been combined in one pack. The magnesium content can be calculated by subtracting the calcium content from the total value of Mg + Ca.

Why test? Invertebrates (stony corals and soft corals, sponges, sea urchins, crustaceans, mussels, snails etc.) and the popular red coralline algae found in marine water require sufficient levels of calcium for healthy growth. The natural calcium level of the sea is 390–440 mg/l. In order for the organism to make the best use of the calcium, the correct ratio of hydrogen carbonate must also be present in the water. For this reason adding calcium compounds without hydrogen carbonate (such as calcium chloride), is pointless. A calcium level of 400–480 mg/l has proved to be ideal for marine aquariums. In addition to calcium, magnesium in sufficient quantities and in the right proportion to calcium is required for the optimal skeletal and shell structure of these organisms. The natural magnesium content in the sea is approx. 1300 mg/l. In the marine aquarium a magnesium content of 1200 to 1400 mg/l has proven to be ideal.
JBL ProAqua Test MgCa Magnesium/Calcium
+ one drop of Mg reagent 2 = 100 mg/l magnesium
+ one drop of Ca reagent 3 = 20 mg/l calcium
+ includes syringe to measure amount of water

JBL ProAqua Mg/Ca Test Kit for Singapore Reef Tanks

Calcium and magnesium are core parameters for any Singapore reef keeper running stony corals, clams or coralline algae, all of which pull calcium from the water to build their skeletons. This combined kit measures both: magnesium can only be read as part of the magnesium-plus-calcium sum, so you measure the total and the calcium separately, then subtract to get magnesium. It is purpose-built for saltwater and pairs naturally with a dosing or balling routine.

Keeping magnesium in its proper range is what lets calcium and alkalinity stay stable together, and instability is a common reason corals fail to thrive in nano reefs squeezed into HDB and condo spaces. Test on a regular schedule, particularly as your coral load grows and consumption climbs, so you can dial in supplements before you see browning or recession rather than reacting after the fact.

For the chemistry behind keeping these in balance, see our calcium and alkalinity stability guide and the calcium and magnesium guide. Find more in our water testing and care range.