ORP (Oxidation-reduction potential) digital water tester accurately and quickly measures organic matter in water with high precision and reliability. Fast response time ensures efficient testing. Ideal for various applications including drinking water, aquaculture, fish tanks, plant cultivation, laboratory testing, ecological research, and swimming pools.Recommended ORP ranges:- Hydrogen-rich drinking water: -150mV to -400mV - Normal drinking water: +150mV to +550mV - Freshwater fish tank: 230mV to 260mV - Seawater fish tank: 350mV to 450mV Features:- High-sensitivity electrode for accurate readings - Removable probe design prevents damage and allows easy replacement - IP67 waterproof rating suitable for brief immersion - 18-month warranty and lifetime customer support Usage instructions:1. Gently remove the protective cap 2. Press the "ON/OFF" button to turn on the device 3. Immerse the electrode in the sample solution (do not exceed the maximum immersion line) 4. Stir gently and wait for the reading to stabilize 5. For temperature measurement, press and hold the "TEMP/HOLD" button 6. After use, rinse the electrode with distilled water, turn off the device, and replace the protective cap Note: When powered on in air, readings may fluctuate normally. Always cover the protective cap after use to prevent the electrode from drying out, which may lead to slow or unstable readings. If the electrode dries, store it in distilled water to rehydrate. To reset the device, press and hold both "MODE" and "HOLD" buttons simultaneously for 3 seconds.