CO2 calculation using PH and KH

CO2 calculation in the aquarium: After we in our Guide article with CO2 fertilization have employed and have also listed everything there that needs to be observed, we would like to go into more detail here about the determination of the CO2 content in the aquarium enter. Above all, the calculation should be an important topic here. Over PH and CH Is there a specific formula for calculating this concentration?

Everything about CO2 in the detailed guide

The methods for determining the CO2 content in water

In addition to the calculation of the CO2 content mentioned above, there are other ways of determining the CO2 content in the aquarium water.

One of them is the determination with various long-term tests by the manufacturers. These are usually determined with indicator liquids. But this only works with a long-term measurement.

Another method of determination is a derivation via calculation. Manufacturers and various information sites on the Internet provide a table where you can easily read your Co2 content via the PH value or the KH value.

Each method has its advantages and disadvantages. For example, when testing with the indicator liquids, no exact statement can be made about the value in mg per liter. In addition, the determination using a table is rather imprecise. We recommend the exact calculation to many more here. However, in order to be able to achieve good values ​​here as well, it is extremely important to know the initial values ​​and not to make any mistakes when determining them.

PH value or also called potentia hydrogenii "strength of hydrogen" can be determined quite easily by droplet tests. However, these are usually quite inaccurate. We therefore recommend measuring with a probe. There are devices available in stores from 30 euros that measure the PH value to two decimal places.

The KH value or carbonate strength is determined quite simply with a droplet test. This should also be sufficient here, because this is given in degrees. The tests are usually applied in such a way that each droplet is valid for one degree of change. If the color changes then you have your KH value.

Both values ​​are used in the following form.

But before we get to the calculation, we want to talk about the guideline values. Here you should distinguish whether you have a densely overgrown aquarium or only a sparsely overgrown tank. Because of this, the CO2 value should also be set differently. Often one differentiates here also the lighting. A tank with less light also uses less CO2, like a tank with strong lighting. You can find out what is strong or weak in our article on lighting. The more light your plants have available, the greater the consumption of nutrients and of course CO2:

Everything about aquarium lighting

Calculation of the CO2 value with a formula

Of course, you should always treat these values ​​with caution.