Why do I need to measure conductivity?

A. You must know the strength of your nutrient solution. If it is too weak, your plants will miss out on the vital elements they need to grow. Too strong and you risk root burn, especially as evaporation occurs within your growing environment. The nutrient solution needs to be measured regularly so you know when to add more concentrated solution or when to add fresh water. Without an instrument to measure it, you are only guessing and run the risk of a failed crop. See Nominal EC and pH Values for Hydroponics Crops.