The Bluelab Guardian is a constant indicator of the desired levels of EC, TDS, pH and temperature, allowing these parameters to be optimized as the crop progresses through each growing phase. A flashing display indicates if one parameter moves away from the desired level, allowing gardeners to make the required adjustments quickly. The Guardian monitors crops 24 hours a day with a built-in alarm system, and also features large, easy-to-read displays with adjustable "Plant Safe" green LED lights, adjustable conductivity and temperature values, push-button pH calibration, a silent alarm for both high and low settings, setting retention even during power failure, automatic temperature compensation, and a water-resistant design. The meter ranges are pH from 0.0-14.0 with a 0.1 resolution, EC from 0.00-5.00 with 0.1 resolution, and temperature from 32-122°F (0-50°C) with 1° resolution. The accuracy is ± 0.1 for pH and EC, ± 2°F (± 1°C) for temperature. Protected by two-year manufacturer's warranty.