TEST GH/KH test kit for measuring general hardness (GH) and carbonate hardness (KH). Test intended for measuring general hardness (GH) and carbonate hardness (KH) of water in aquaria and ponds, using the titrimetric method. It is convenient and extremely easy to use. The relevant reagent solution is added to the water drop by drop until the colour changes. One drop of reagent corresponds to one German degree of general hardness (°dGH) or carbonate hardness (°dKH). Many fish species are characterised by wide hardness tolerance. However, in some species the correct level of hardness is important for good health and reproductive success. The higher the carbonate hardness (KH), the more stable the water reaction, although it makes decreasing of pH more difficult, when the fish kept require that. For further water inspection we recommend other Tropical tests.