Safer® Hydro FAQ: What is TDS?
Total Dissolved Solids, or TDS, is the measurement of the density of nutrient solution. TDS, typically expressed in parts per million (ppm), tells you how concentrated the nutrients are. So you can be sure your plants are getting the exact amounts they need – excessive nutrients can cause serious, irrevocable damage to your crops, create a hospitable environment for destructive fungi, and clog up your hydroponic system.
A nutrient solution with 700 ppm means that there are 700 milligrams of dissolved solids present for every liter of water.
An Electric Conductivity (EC) meter is an easy way to determine the TDS in your nutrient solution.