Understand the hardness of your aquarium water.

Reduce or increase the hardness of your water?

Here are some simple explanations of these water parameters.

The water in your aquarium has various chemical parameters. Generally, the first that comes to mind is Ph, but water hardness is just as important to understand to maintain the good health of fish, plants, snails or even shrimp.

Depending on where you live, you may find that tap water is more or less calcareous.

When you have hard water, whitish deposits regularly settle on the shower walls or even on the kitchen sinks. You can also see white marks on the glass of your aquarium, it is hard water. It is water that is loaded with various mineral salts such as calcium, magnesium or even sodium, and conversely, soft water; it is a water that has few mineral salts.

Understand water hardness.

But then, how to explain that some will have hard, even very hard tap water, and others rather soft water?

Each region has one or more collection points for distribution water. The water that flows to our taps is captured from groundwater tables located deep underground. And this water traveled a very long way before arriving in these underground pockets. Falling from the sky, rainwater will cross the ground and different layers of earth, rocks, sand. And by crossing these different layers, the water will gradually take on various mineral salts.

Each region, each department has a different soil, so it is the quality of the soil that will condition the quality and hardness of tap water.

Difference between the total hardness and the carbonate hardness of water.

Total hardness or GH.

Total hardness measures only the calcium ions and magnesium ions present in the water. The higher the total hardness, the harder your water can be called.

Total hardness measures only certain mineral salts and not all present in the water. True total hardness is measurable by conductivity.

The carbonate hardness or KH.

It only measures the carbonates and bicarbonates present in the water. The measurement of the carbonate hardness allows us to know if the pH of the water is going to be stable or not.

So the higher your KH, the more stable your Ph will be. But a KH of 4 or less will cause your water to have an inconsistent Ph. KH is an important measurement, especially when you want to change your pH or want to use CO2 in your aquarium.

For a simple freshwater community aquarium, we recommend a KH close to 7. Note that in saltwater aquariums, the KH is also tested.

A marine aquarium should ideally have water with a KH between 8 and 9. Note that the main water parameters are closely related. KH is related to Ph and the amount of CO2 present in your water. These three parameters always go together. Again, if you have a KH greater than 4 your Ph will be more stable, but also difficult to modify.

If you add CO2 gas to your aquarium, it will only drop your Ph if the KH is below 4.

In our aquariums, some species of fish will prefer hard water and others soft water.

In nature, the water of rivers, streams or lakes does not all have the same GH and the same KH. It will therefore always be necessary to be well informed about the fish or invertebrates that you want to welcome in order to possibly adapt the hardness of the water to their specific needs. This is all the more important for fragile or wild species as well as if you wish to have reproductions.

Here are some examples,

Platinums, guppies, moli, griffins or even goldfish generally prefer medium hard water, very hard as far as moli are concerned.

Freshwater plants, on the other hand, will prefer moderately soft water, as they still need some mineral salts for their growth and development.

Water that is too soft or water that is too hard will not suit them.

Tap water, in France anyway, is generally hard, even very hard. This will not really be a problem for some species of fish, but for others, we may have to modify the hardness of our water.

Test the hardness of your water.

First of all, you have to test the total hardness and the carbonate hardness, the GH and the KH of your tap water. To lower the GH and KH of your water, the solution is to cut your tap water with softer water. To do this, you can use reverse osmosis water or even bottled mineral water.

It is rare, but always possible to increase the GH or KH of your aquarium water. There is a product that develops and increases the KH+ in your pond and improves water quality . It is an additional supply of minerals that allows plants and fish to develop well .

In any case, if you want to modify your GH or your KH voluntarily, you will have to do it gradually, especially if your pool is already populated.

When you start or want to voluntarily modify your GH or your KH, you must do a control test of these parameters at least once a week. Then you can do a control test only once a month.

Well, we hope this article has helped you understand a little better the hardness of the water in your aquarium. Above all, do not hesitate to reread the article to fully understand, in particular, Ph, CO2, conductivity. This will give you an overview of the water parameters in your aquarium.

We hope you enjoy your fish and your aquariums.