TDS Meters by HM Digital, Hanna and Extech
TDS (Total Dissolved Solids) is a measure of the combined organic and inorganic dissolved substances including minerals, metals, and salts. Dissolved Solids come from organic sources, water runoffs, water suppling pipes, industrial waste, and sewage. TDS are reported in mg/L (milligrams/liter) or ppm (parts/million). Water can be classified by the level of TDS: Fresh Water < 500 ppm, Brackish Water 500 to 15,000 ppm, Saline Water 15,000 to 30,000 ppm, Sea Water 30,000 to 40,000 ppm and Brine 40,000 to 300,000 ppm.