What IS TDS? Total Dissolved Solids(TDS) are the total amount of mobile charged ions,including salts or metals dissolved in a given volume of water. TDS,which is based on conductivity,is expressed in parts per million(ppm) or milligrams per liter(mg/L).TDS includes any inorganic element present other than the pure water molecule(H2O) and suspended solids. Â The higher the TDS level in water, the greater the of probability of harmful contaminants that can pose health risks or hinder the absorption of water. The U.S. EPAâ??s Maximum Contaminant Level of TDS for human consumption is 500 ppm. Â Use the TDS Meter to: Check the performance of your water filter Check for the hardness (1 grain=17ppm) Make sure you always drink pure water. Range:0-9999ppm resolution: power:2*1.5v Calibration:1 point dimension:152*30*15mm N.W:46g g.W: 76 Product size:155*31*23mm(6.1*1.2*0.9in) Carton size: 410x390x370cm Package:200pcs/carton, 15kg/carton, 1pcs/ white box (cheaper) -