Total Dissolved Solids (TDS) is defined as the amount of solids dissolved in a solution. Electrical Conductivity (EC) is defined as the ability of a solution to conduct an electrical current. EC/TDS meters have two electrodes with an applied AC voltage which are placed in the solution. This creates a current dependent upon the conductive nature of the solution. The meter reads this current and displays in either conductivity (EC) or ppm (TDS). EC and TDS meters, monitors and testers are available from Bluelab, Hanna, and Milwaukee from Plant Lighting Hydroponics at very economical prices.
$87.95Bluelab Truncheon Nutrient Meter - The World’s favorite conducti...
$87.95Bluelab Commercial Truncheon Meter - designed for hydroponic crops tha...
$63.99Bluelab PPM Pen - Measure E - PPM and Temperature