This total hardness, or GH value indicates the amount of dissolved magnesium and calcium.\nThose salts are directly responsible for many physiological processes of all plants and animals.\nBeside the physiological processes the salt stablilize, the KH value.\nSome fish and plants require a higher GH level, other fish who naturally live in water with lower hardness, require a lower GH level.\nKeep out of reach of children.\nContent: 2 x10 ml test reagent, measuring cylinder, instructions.