what is TDS in water
Total Dissolved Solids (TDS) are the total amount of mobile charged ions, including minerals, salts or metals dissolved in a given volume of water, expressed in units of mg per unit volume of water (mg/L), also referred to as parts per million (ppm). (Suspended solids are any particles/substances that are neither dissolved nor settled in the water, such as wood pulp.). 2  In general, the total dissolved solids concentration is the sum of the cations (positively charged) and anions (negatively charged) ions in the water.