Tests tap water or pond water for carbonate hardness (KH). Can be used to determine the proper dose of pH buffers which control your pH.
Tap water rarely provides the water conditions necessary to maintain optimal pond water chemistry. Low KH can contribute to wide pH swings in your pond. Topping off your pond with tap water can add minerals to your pond, resulting in a steady increase in GH. It is therefore necessary to test the GH and KH frequently to monitor water quality and prevent stressful conditions from occurring.