EC / TDS / PPM Meters For Hydroponics

Electrical conductivity (EC) measures the water’s ability to conduct an electrical charge. Total dissolved solids (TDS) is a measure of the combined content of all inorganic and organic substances contained in a liquid in molecular, ionized or micro-granular suspended form. Growers use EC meters to measure the EC levels of their nutrient solutions. The meters measure EC either in mS/cm (millisiemens/cm) or μS/cm (microsiemens/cm). The conversion of μS/cm (microsiemens/cm) to mS/cm (millisiemens/cm) is 1,000 μS/cm = 1 mS/cm.  TDS meters are really EC meters in disguise. 

A TDS meter reads the EC of the dissolved salts in the solution and uses a conversion factor to provide a ppm reading. Conductivity is really a measure of the nutrients in the solution. Low conductivity implies a low nutrient concentration, which usually results in nutritional deficiencies and slow growth rates of your plants. One can look at the situation, as a higher conductivity is more food for your plants. However, be careful of very high levels as this can burn and or kill the plant.  Monitoring your TDS or EC readings is important. Doing so helps you understand if you’re feeding your plants too much or not enough. If you’re new to growing, using a well-balanced feed is probably a good place to start.

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