The pH meter is an electronic device that indicates the level of acidity or alkalinity of a solution. In other words, the pH determines the availability of minerals to plants.
How to use a pH meter in Hydroponics: Calibrating pH meter
The meter is calibrated to a known pH value because the characteristics of the electrode change over time. Therefore, frequent calibration is essential in order to obtain accurate and reliable readings.
Calibration methods include single-point, two-point and multi-point calibration. Generally, a 2-point or 3-point calibration is recommended.
Important things
- The pH buffers must be at the same temperature as the sample. If this is not the case, you have to do temperature compensation.
- Between buffers you should rinse the electrode with distilled water.
- Also, do not rub or clean the electrode bulb to avoid polarization errors.
Step 1
Pour about 20-30 mL of each pH buffer into 50 mL beakers. Next, select the calibration mode on the meter. Then, rinse the electrode with distilled water and dry it with a microfiber cloth.
Step 2
Immerse the electrode in a pH 7 buffer solution, then shake the buffer evenly. Wait until the meter stabilizes and reads 7. If it does not, rinse it with distilled water, dry it and repeat the procedure.
Step 3
Rinse the electrode with distilled water to remove any traces of the solution and dry it.
Step 4
Repeat the process with the next calibration point (pH 4 or pH 10).
How to use a pH meter in Hydroponics: pH Measurement
It is essential that you take samples close to the roots and not at the surface because nutrients and salts become concentrated and therefore do not reflect the actual fertility of the roots.
It is also advisable to gently shake the meter to remove bubbles in order to get an accurate reading.
Step 1
Rinse the electrode with distilled water and dry it with a lint-free cloth.
Step 2
Place the electrode in the sample. When the reading is stable, record the pH.
How to use a pH meter in Hydroponics: pH meter Maintenance
Periodically observe the pH meter for bumps, cracks, debris, etc.
You can store it in a 4 M KCl solution or pH 4 or 7 buffer solution. I do not recommend storing it in distilled water because the electrode may be damaged.