Salifert Magnesium Test

The Salifert Magnesium Test is a simple and quick droplet test.

Information about the water test:

• Measuring range: 30 - 1500 mg/l
• Resolution: 30 mg/l
• sufficient for 50 tests

Measuring magnesium in seawater - why?

Magnesium plays a minor role in your aquarium in its direct form, as it is only used by a few organisms. These include, for example, calcareous algae, soft corals, gorgonians, sea urchins, starfish and mangroves. Stony corals do not need magnesium ions to form their skeleton.

Nevertheless, magnesium ions are an important component of various biochemical reactions and processes, such as photosynthesis. In addition, magnesium indirectly ensures a more stable calcium supply by preventing the precipitation of calcium carbonate and thus stabilizing the calcium and KH values. You should therefore ensure that the magnesium concentration in your aquarium water is in the range of 1250 to 1350 mg/l.

Adjusting the magnesium level

Depending on your stock, a weekly water change with a high-quality sea salt of 10% may be sufficient to ensure an adequate supply of magnesium.

If the magnesium content falls below the optimal range (< 1,200 mg/l), you should slowly increase it. To do this, you can either use commercially available ready-made products such as Tropic Marin Bio-Magnesium or make your own stock solution.

To prepare the stock solution, dissolve a total of 836 g of magnesium chloride hexahydrate (MgCl ₂ *6H ₂ O) in one liter of osmosis water. Adding 10 ml of the prepared solution increases the magnesium concentration in 100 liters of your aquarium water by 10 mg/l.

For example, if you want to increase the magnesium content in your 300-liter aquarium from 1,200 to 1,320 mg/l, you need to add 360 ml of the stock solution. However, you should also spread the addition over a few days so that the increase in magnesium concentration does not occur too abruptly.

If the magnesium concentration in your tank is too high, temporarily stop adding magnesium or carry out a partial water change (if the values ​​are very high > 1600 mg/l).