General Hardness of Water (GH)

Last updated: November 18, 2021

What Does General Hardness of Water (GH) Mean?

General hardness (GH), or the general hardness of water, refers to the combination of calcium and magnesium ions that are found in water. The general hardness of water is important because it affects the water’s pH level, which is crucial for aquaponics and hydroponics.

General hardness test kits are widely available at hydroponic gardening stores or aquatic suppliers. The test kit measures the overall concentrations of calcium, magnesium, and other ions in the water to determine the water’s general hardness.


Maximum Yield Explains General Hardness of Water (GH)

Many people mistakenly believe that the carbonate hardness and general hardness of water are related and virtually the same. However, both are distinct and in many instances, a water test's results will reveal that they are actually far removed from each other.

In some areas of the world, the water’s carbonate hardness level is higher than the general hardness level. Also, water softeners, which are widely used in Europe and the United States, cause a high level of carbonate hardness and low general hardness.

Water with a low general hardness level is considered to be soft water and water with a high general hardness level is considered hard. Most aquatic species do not thrive in hard water.

The general hardness levels of the water can be reduced in numerous ways, such as adding peat moss to the water, installing a reverse osmosis system, adding rainwater to the hard water, placing pieces of driftwood in the water, or purchasing commercially available water softeners.


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HydroponicsAquaponicsWater SupplyMetering & MonitoringPlant HealthpH

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