What is GH in an aquarium?

What is the GH of my aquarium water?

The water in our aquariums has different chemical parameters. Generally, the first that comes to mind is PH. However, water hardness (or GH) is just as important to analyze to keep your fish and shrimp healthy.

What is the definition of an aquarium's GH?

Depending on where you live, tap water contains more or less limestone. And when you have hard water, whitish deposits regularly settle on shower walls or kitchen sinks. Moreover, you can also see white marks on the glass of your aquarium. In fact, hard water is hard and very mineralized water. Conversely, fresh water has few mineral salts.

Why is the water more or less hard depending on the region?

The water flowing through our taps is located in water tables (very deep layers located underground). However, this water followed a long way before arriving in these underground pockets. Falling from the sky, rainwater passes through the different layers of earth, rocks and sand in the ground. This is how the water will gradually take on various mineral salts.

The quality of the soil in your area determines the hardness of tap water. However, in order to understand the hardness of your aquarium water more precisely, it is necessary to understand the difference between the total hardness called GH and the carbonate hardness called KH.

GH vs KH: what are the differences?

In the field of aquariums, German measurements are used worldwide. GH degrees are the abbreviation of GesamHärte (total hardness in French) and KH degrees are the abbreviation of KarbonatHärte (carbonate hardness in French).

Note that there are also French measures like the TH which is the equivalent of the GH as well as the TAC similar to the KH. You can find these measurements on your water bills. Indeed, the water unions use French measures. The GH relates to the calcium and magnesium ions present in the water of your aquarium while the KH makes it possible to measure the level of carbonates and bicarbonates.

What is the ideal GH level for my aquarium?

For a community aquarium, the GH level should be between 6 and 16° GH. Water is very soft when it has a GH level of less than 6° and it is very hard when it exceeds 9°. In order to lower your GH level, we advise you to dilute its mineral content.

There you go: you know everything there is to know about the GH of an aquarium!

To conclude, note that this GH level can be adapted if necessary. And if the test indicates a GH level that is too high or too low, it is even necessary to rebalance it. The health of your fish is at stake!

Want to know more about the chemical composition of your aquarium water? Check out our other blog posts on the subject.