... Tds range:0~9999ppm 4. Easy to operate 5. Portable style TDS control system: 1. What is TDS?Total Dissolved Solids ( ... , food processing, physics & chemistry teaching, water treatment, cosmetics, wine, home, office, travelling and more. Functions:DisplayLCD, 34mm x 17mmVoltageCR2032 Battery ... 200-360 ppm: Washing Water above 360ppm: Polluted Water 5. Testing: TDS≥40ppm, red light TDS<40ppm, green light ...