TM KH Test

The carbonate hardness (KH) or alkalinity of a water sample characterizes the buffering capacity, i.e. the ability to maintain the pH value of the water. In water chemistry there are several terms used to describe the buffering capacity with different definitions. In aquaristics the term "carbonate hardness" is commonly used, but alkalinity is measured. In this test both terms are used synonymously. The carbonate hardness is usually given in degrees of German hardness (°dH). The carbonate hardness should be checked with great regularity in all aquaria. If the alkalinity in the aquarium is too low, the pH-value may drop (acid drop), which is life-threatening for many fish and invertebrates. In reef aquariums a sufficient carbonate hardness is essential for strong coral growth. In saltwater aquariums, the carbonate hardness should be between 6 and 9 °dH. In freshwater aquariums, the carbonate hardness should not fall below 3 °dH.