Regularly measuring the EC value of the nutrient solution or the growing medium is essential, especially for hydroponic cultivation. But even when growing on soil, optimal results can only be achieved with a nutrient content of the water that is ideal for the plant. This can be determined easily and quickly with an electronic EC meter. Therefore, we would like to briefly introduce you to the correct use of an EC meter. You can read more about the EC-value in our report about the EC value in cannabis growing.
Determine EC value
Measuring the EC value of a liquid with an electronic EC meter is very easy. The device is switched on and the measuring probe is held in the liquid. After a short time, the value can be read in the display.
Before measuring the EC value of a nutrient solution, all fertiliser components must be added and the nutrient solution must be stirred well.
If the EC value is too high after the measurement, the nutrient solution must be diluted with neutral water until the desired value is reached. If the EC value is too low, carefully add more fertiliser until the correct value is reached.
Please note that additives such as root boosters, enzymes, flower boosters, etc. do not usually increase the EC value, as they do not contain mineral salts.
Calibrate
Calibration of the EC-Meter is essential for accurate measurement. If an EC meter is not calibrated before the first measurement and regularly thereafter, it will become increasingly imprecise over time and will no longer show correct values.
An EC meter should be calibrated:
- before the first measurement
- subsequently every fortnight
- After cleaning
- when the results become inaccurate
To calibrate an EC device, you need a calibration liquid. For this, it is best to read the instructions of the respective device manufacturer to find out which liquid (EC value) is needed or to use the calibration solution of the manufacturer.
The calibration liquid should not be kept until the next measurement, otherwise it will no longer function correctly. Therefore, always fill only as much liquid into a small container as is needed and do not pour it back into the bottle!
Most devices are calibrated with a small screwdriver via a small screw. To do this, hold the measuring probe in the calibration liquid and carefully turn the screw until the value of the calibration liquid appears in the display. For instruments that are digitally calibrated, the procedure is described in detail in the instruction manual. In most cases, the calibration mode must be selected and the probe immersed in the appropriate liquid until the display stops flashing.
How do you clean an EC meter?
The electrodes must be cleaned regularly to ensure accurate measurements. Salt residues, grease from the fingers or even dust will falsify the measurement results. Therefore, the device should be cleaned after each measurement and preferably stored in demineralised (distilled) water between measurements. For regular cleaning, there are also special Cleaning liquids are available for regular cleaning.
Here are some EC meters that are very suitable:
Hanna Dist 4
Low-cost EC meter with a robust graphite probe that requires little maintenance and measures very accurately. Hanna DIST 4 is not waterproof and cannot be submerged.
Adwa AD31
The ADWA AD31 is a waterproof EC meter for the small purse. Accurate determination of electrical conductivity is child's play and can be carried out very quickly.
Hanna Combo Meter
The Hanna Combo-Meter measures the EC value, the pH value and the water temperature. This gives you a simple and effective control of all parameters of the nutrient solution.
Bluelab Guardian Monitor
The Guardian Monitor from Bluelab reliably monitors EC value, pH value and temperature of the nutrient solution via two probes that simply hang in the water. One pH probe and one for the EC value and temperature. All three parameters can be read at a glance on the large screen. For professionals, an excellent and reliable solution.
