Aquasonic Hardness Test Kit (Fresh Water)

This HARDNESS TEST KIT measures the sum of the calcium and magnesium concentrations, expressed in ppm (parts per million). This is, in essence, measurement of the permanent hardness of water, but the measurement may also contain some temporary hardness in the form of calcium dissolved by carbon dioxide in water. This form of temporary hardness is usually minimal.

HOW DOES WATER BECOME HARD?
Water hardness results from dissolvedcompounds of magnesium and calcium.
With temporary hardness, magnesium and calcium are dissolved by carbon dioxide in water. This process can be reversed by removing the carbon dioxide, e.g. By boiling, or as aquatic plants use carbon dioxide. However, if the salts of magnesium or calcium are dissolved as a result of an acid present in water, the hardness becomes permanent.

WATER HARDNESS IN THE NATURAL STATE
The degree of hardness varies not only from country to country but river to river and even the hardness in each river varies from season to season. Aquatic life have different requirements according to geographical location and though most fish can stand a great deal of variation in hardness, they do best at specific levels. Factors like breeding of a species, the colour of a species or even the inhibition of fungal diseases can be greatly enhanced by the hardness of water.

SPECIES REQUIREMENTS
Examples of fish that live at or below 150ppm are Angels, Corydoras, Catfish, Discus, Gouramis, Loaches, South American Tetras. Examples of fish that live between 150ppm and 300ppm are some Australian Natives, Guppies, Sword Tails, Mollies, Platties, and Goldfish.
Examples of fish living above 300ppm and usually under 500ppm are African Cichlids, and Brackish water species.