It also contains a mini amplifier to boost the electrode signal and render the meter impervious to noise and interference. The large display has also numerous graphic symbols that guide you through the operations. Other characteristics of HI 991000 include a stability indicator for the pH electrode which helps non-technical users to determine when to take the pH readings. The battery life of the meter guarantees over 1000 hours of continuous use. Another unique feature is that the LCD shows in percentages how much battery power is left, so that you receive early warning of weak batteries.
Calibration is performed automatically by the instrument at one or two points.
The user can select the calibration buffers between two sets of pH 4.01, 7.01 and 10.01 or pH 6.86, 7.01 and 9.18. All calibration and user settings are maintained even during and after battery replacement. The optional shockproof boot will protect your meter against bangs and falls.