The function of a nutrient solution or fertilizer mixture is to supply the plant roots with water, oxygen and essential mineral elements in soluble form. The pH of nutrient solution decides the availability and absorption of nutrients by each species of plant. Every plant species has a preferred pH range in which it will grow best. Trans Instruments HortiCare pH check tester is specially designed with advanced features to ensure fast and accurate pH test. Features: Hold Function; Beep Function: Able to beep to signal the beginning and end of each function; One-touch Calibration; Auto-lock Function: Intelligent sensing of end reading when enabled; Auto Shut Off: Automatic shut off to conserve battery; Low Battery Indicator: Automatic alert to change battery when needed; Operating Range: 0 to 14.0 pH; Resolution: 0.1 pH; Accuracy: ?0.2 pH; Battery: 4 x 1.5V Button Cell (LR44).