General description A very complete kit to check the quality of your water, from the tap to the treatment, including for aquariums and swimming pools. This 4-in-1 pH tester is compact and lightweight, resembling a pen, making it easy to handle for various applications such as drinking water, beverages, aquariums, hydroponics, and swimming pools. Technical specifications pH measurement range: 0.00 to 14.00 TDS measurement range: 0 to 19,990 ppm Installation No tools are needed for calibration; simply immerse the pH meter electrode in the solution. Usage Press "ON/OFF" to turn on the electronic pH meter. Shake gently and wait a few seconds for the readings to stabilize. The TDS water freezes the measurement result when you press the "HOLD" button and turns off automatically after a few minutes of non-use.