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Hydroponic measuring instruments: water, PH, EC …

Plants need specific conditions to thrive: nutrients, temperature, pH … Everything must be perfect! Fortunately, in hydroponics, you control everything. Nevertheless, to control everything, you have to measure. To do this, you will need a small arsenal of equipment to check the variables of your crop.

Equipment for measuring electroconductivity (EC)

The electroconductivity of a solution is its ability to carry an electric current. It tends to increase as the concentration of certain minerals increases: potassium, phosphate, nitrate and sulfate in particular. In hydroponics, this indicator is used to show if the solution is rich in minerals or not.

It is measured in microsiemens per cm (mS/cm). There are several types of measuring instruments:

  • Amperometers using two poles
  • Potentiometric sensors using 4 electrodes

It can also be measured in Total Dissolved Solid (TDS), giving the amount of ions in a solution. This is equivalent.

Note that to measure electroconductivity, the temperature must be controlled. Indeed, the hotter the water, the more easily electricity is transmitted.

Tools for measuring acidity (pH)

Your solution should be neither too acidic nor too basic. It is estimated that the ideal pH for the absorption of nutrients by plants is around 5.8. There are three methods:

  • Using pH paper. You dip a small paper containing a reagent in your solution and it will change color according to the pH. This method, if very expensive and simple, is not very accurate.
  • The use of a liquid measuring the pH. In the same idea as the pH paper, it is a reagent that allows to evaluate the pH of the water in which it is found. It is even less accurate, especially if your water is cloudy.
  • The ideal is to use a digital pH meter. You can set up an automated alert system.

Then you can adjust the pH with solutions whose names describe the function quite precisely: “pH up” and “pH down”.

Temperature measurement

The temperature of your nutrient solution is important for several reasons: on the one hand, warmer water contains less oxygen and facilitates the development of bacteria and fungi. On the other hand, water that is too cold can damage your plants. The ideal temperature is generally around 18-20°C.

To cool down the water temperature, there are electric water coolers.

Versatile devices

Some tools allow you to control all these data. This is for example the case of the

Bluelab Monguacon (379e)