Organic nutrients aren't the same as synthetic nutrients... Synthetic nutrients are salt, and are measured by the EC meter.
Salt conducts electricity, and the more salts there are, the higher the electricity is conductive.
Organics are broken down by your micros, and they are converted into the same chemicals as the synthetic nutrients, and then consumed by your plants... but they don't show up as salt, therefore, you cannot measure the electric conductivity.
In other words, organics are broken down into the same nutrients as you are adding when you dose it with synthetic nutrients... except the microbes are doing the work, and making it available to the roots.