Salifert Calcium Test

The Salifert Calcium Test is a simple and quick drop test.

Information about the water test:

• Measuring range: 10 - 500 mg/l
• Resolution: 10 mg/l
• sufficient for 50-100 tests

Measuring calcium in sea water - why?

All animals that form a calcareous skeleton or shell require both calcium and carbonate ions. A sufficient supply of these two ions therefore plays an important role, especially for the growth of the stony corals in your tank.

In the seas, the average calcium content is around 420 mg/l. The calcium concentration in your aquarium should ideally be in the range of 400 to 450 mg/l. Note that the formation of lime, i.e. calcium carbonate, can only occur if the concentration of carbonate ions is high enough. This is the case if the alkalinity of your tank is in the range of 7.0 to 9.0 °dH.

Due to the calcification processes taking place in your aquarium, the calcium content and alkalinity are continually decreasing. You should monitor this process by regularly measuring both values ​​and take action to regulate them if necessary. In practice, various supply systems have proven effective in maintaining the calcium and carbonate concentration (including the Balling method, Carbo-Calcium, All-for-Reef & calcium reactor).

Adjustment of calcium level

As mentioned before, calcium ions are consumed during calcification, so you need to add calcium to your aquarium at regular intervals.

To increase the calcium concentration, you can either use commercially available ready-made products or make your own stock solution.

To do this, you need to dissolve 800 g of calcium chloride dihydrate (CaCl ₂ *2H ₂ O) in one liter of osmosis water. 4.59 ml of this solution increases the calcium concentration in 100 liters of your aquarium water by 10 mg/l.

For example, if you want to increase the calcium content in your 300-liter aquarium from 400 to 420 mg/l, you need to add a total of 27.54 ml of the stock solution. The calcium concentration should always be increased slowly, which is why you should not add the required amount of solution to your tank all at once, but gradually.

Another method where you only increase the concentration of calcium ions in your tank is the addition of lime water. However, you cannot calculate or determine the amount of calcium ions added. The lime water method has other disadvantages, which is why you should inform yourself about the different aspects of this method before using it.

When adding calcium ions, you should keep an eye on the alkalinity, as calcium and carbonate ions are usually consumed in a fixed ratio. Using the so-called Balling method, Carbo-Calcium or operating a calcium reactor, these two ions are added to your aquarium in a balanced ratio.

Regular water changes also help to stabilize the calcium concentration.

If the calcium concentration in your tank is too high, you should temporarily stop adding calcium ions. Simply wait until the calcium content has dropped to the desired level. You should always keep an eye on the alkalinity and take action to regulate it if necessary.