Compact digital TDS meter for quick, reliable checks of total dissolved solids (ppm) in water. Turn it on, immerse the probe, wait for a stable value, press HOLD to lock the reading, then remove and record. Ideal for household drinking water, aquariums, hydroponic nutrients, pools/spas, and more. Includes auto-off to save battery and a clear LCD for easy reading. PPM guide: • 0–50 ppm — High-purity water • 50–100 ppm — Pure water • 100–300 ppm — General pure water • 300–600 ppm — Water may form scale • 600–1000 ppm — Poor taste water • >1000 ppm — Not suitable for drinking