A “Conductivity Meter” or “EC Meter” (also known as “mS”, “cF” or “TDS”
meter) is a device used to help monitor the concentration of nutrient
solutions.
‘Conductivity’ represents the ease with which a solution conducts
electricity. Numerically it is measured in units called Siemens.
Solid substances known as
'salts' (e.g. sodium chloride, potassium
nitrate),
yield 'ions'
when dissolved in water. 'Ions' permit the flow
of electricity through the solution. Increasing the
concentration of ions improves the ease with which the solution carries a
current and therefore causes a higher conductivity.
Liquids such as petrol and pure water are essentially non-conductors of
electricity. Further, many water soluble substances
do not conduct electricity
when dissolved in water e.g. sugar and alcohol. This occurs
because these liquids/solutions contain very few 'ions'.
