EC meters are an electronic device which are used in hydroponics to measure the electrical conductivity of your nutrient solution. They tell you if your plants have the right amount of nutrient in their solution. As a general guide and with some exceptions, the optimal EC range of your nutrient solution should be between 1.5 and 2.5. Please see our Complete EC & pH levels chart for hydroponic plants for more information. We stock EC meters and pens from Bluelab, HM and Milwaukee.