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. Each plant has its preferred nutrient concentration to facilitate the absorption process to the roots. Trans Instruments HortiCare Nutrient concentration check tester is specially designed with advanced features to ensure fast and accurate concentration test. Features: Precise PPM Measurement: Uses commercially acclaimed 700 measuring factor; Auto-Lock Function: Intelligent sensing of endpoint reading every time; ATC Function: Readings are automatically temperature compensated; Beep Function: Able to beep to signal the beginning and end of each function; Single button calibration; Auto Shut Off: Automatically shuts off to conserve battery; Low Battery Indicator: Automatic alert to change battery when needed; Operating Range: 0 to 1,990ppm; Display Resolution: 10ppm; Accuracy: ?5% full scale; Calibration Point: 990ppm (KCl); Battery: 4 x 1.5V Button Cell (LR44 equiv.).