pH 1 Test ( Design for Freshwater ): PH value shows the acid or alkaline state of water ( pH value equals 7 is neutral, it is alkaline as pH value is greater than 7, and acid as pH value is is less than 7 ), most of the fish can adapt to life in the water around pH=7, but many species have special water preferences. Such as the species of pH <7: Discus, Amazon cardinals, preferences for pH=6.0 to 6.5 and the right pH value range keep the fish healthy.
pH 2 Test ( Design for Marine ) : In all tanks, the pH level is important. Marine tanks especially need regular testing to ensure that the pH level is correct. The pH level denotes how acidic or alkaline the water is. In saltwater aquarium, it's generally more alkaline which is beneficial to reef and marine life. Such as species of pH > 7 : Marine fish preferences for pH 8.4 and African cichlid preferences for pH 7.5 to 8.0.
GH Test ( General Hardness ) : The salts of calcium and magnesium are major constituents of general hardness (GH). This means it is very import element for those plants and need higher general hardness demand, and the plant lesions like shrinkage of tip, twist of leaves and abnormal development always happen in low general hardness condition. To accurately know the general hardness value is the key way to keep successfully a plant aquarium. Normally the GH value shall be kept in 7-9 degree (dGH, Deutch General Hardness)
KH Test ( Carbonate Hardness ): The insufficient KH ( carbonate hardness ) will suddenly change the stable pH of water. The rapid fluctuation of pH will severely impact the life of an aquarium, and then ruin the normal ecological system. Therefore, to keep the correct balanced of KH value and to test KH range regularly is a significant procedure to maintain the optimum aquarium.