How Strong Are My Nutrients? 
EC and TDS Meters Explained

Any serious grower needs a sure fire method of accurately testing the strength of their source water, nutrient solution and run-off so they are equipped to respond to their plants’ ever-changing needs. So, to help us in our quest for perfect plant nutrition, we have all sorts of nutrient products, additives, meters, monitors, feed charts, calibration fluids and acronyms buzzing around our local grow store. You’ve probably heard people talk about the “EC” of their nutrient solution, or perhaps they talk in ppm (parts per million) – or they recommend you use a “TDS meter”. What’s with all this jargon? And how does it all fit together?