While deciding on the best pH meter is the first concern, growers and scientists must consider knowing how to store pH meter electrodes for long-term use are also of high importance.
By maintaining your pH meter well you will extend its lifespan and ensure that your measurements are as accurate as possible. The pH probe’s maintenance is of special importance because this part does the actual measuring.
How Do pH Meters Work?
The parts that makeup Lab pH meters are typically made up of two major components: a probe and an electronic measuring display.
Within the probe are two electrodes, including the sensor, or measuring electrode, and the reference electrode. These two electrodes work in conjunction with each other like a battery. Once the probe is placed in a liquid solution, H+ ions in the solution displace metal ions on the probe, thus creating an electrochemical flow.
The pH meter senses this flow and converts it into a corresponding pH value by comparing the generated voltage from the sensor electrode with that from the reference electrode.
How to Clean, Store, and Maintain the pH Probe of your pH Meter?
pH meters are sensitive instruments, so it is thus critical to understand cleaning procedures and how to store pH meter electrodes properly after each use.
Here are a few tips for pH probe maintenance.
Avoid direct contact
Avoid direct contact with the sensor. This causes damage, which will cause the pH meter to get large discrepancies. If contact is unavoidable, use soft paper to handle the probe (e.g. A tissue).
Rinse after use
Pre-rinse the probe with demineralized water and immerse it in a cleaning solution after each use. This is especially important when measuring materials or solutions that contain nutrients, minerals, and proteins. This way you will remove residue from the probe which minimizes your chances of damage.
Store damp
Store the pH probe damp. This prevents contamination from drying onto the probe. Place some electrode storage solution into the protective cap. Never use tap or demineralized water for this, neither is appropriate for this procedure
Calibrating
If your measurements are not stable, you will need to calibrate your pH meter. You will determine the deviation of the pH meter by comparing values to standard values, so will know how far out your meter is.
Watch this 5-minute Youtube video for more info on how to calibrate your pH meter.
pH & TDS Electrode Cleaning Solution
NutriHydro TDS and pH General Purpose Cleaning Solution
Along with regular calibrating, the pH meter electrode needs to be cleaned between each use to prevent contamination of the substances being measured.
pH meters use glass probes that are submerged into the substances being measured.
The probe uses ions to attract other ions in the substances. It needs to be cleaned after every use.
Nutrihydro TDs and pH cleaning solution is specially formulated to thoroughly clean TDS and pH meter electrodes that could clog their sensor tips.
How to Use:
Immense the electrode in the cleaning solution for 15-20 minutes to dissolve deposits. After every soaking, the electrode should be rinsed with distilled water. Droplets adhering to the electrode should be gently dried with tissue paper and not rubbed or wiped.
Where to Buy:
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pH & ORP Electrode Storage Solution
NutriHydro pH and ORP Electrode Storage Solution
At all times, the glass tip of the pH meter probe should be stored in a tube filled with an acidic solution.
The probe must never be stored in distilled or deionized water for long because the water will remove ions from the probe through diffusion, which can degrade the probe and its measurements.
NutriHydro pH and ORP Electrode Storage Solution helps to keep the glass membrane hydrated while the sensor is not in use. Its formula includes active ingredients to prevent organic matter from growing around the sensor tip.
How to Use:
After cleaning, fill the cap of the pH meter at all times with the solution.
Where to Buy:
Similar Product on Amazon:
pH Meter Calibration Powder
A buffer solution is needed for calibration of pH meter as they resist the changes in pH if you accidentally add a little acid or base or even water and are stable for a longer period.
It also maintains a relatively constant pH in a solution as well as a constant internal environment.
Individual packets help to keep the solution fresh until use.
How to use:
Watch this 5-minute Youtube video
Where to Buy:
Correct Handling and Care of TDS, ORP, and pH meters
A pH electrode is fragile and one should not be tempted to use it as a stirring glass rod when adjusting pH.
A pH meter needs to be calibrated regularly with the help of standard buffer solutions.
pH readings are temperature-sensitive due to changes in glass electrode resistance. A 10-fold increase in resistance results for every 30°C rise in temperature. Avoid temperature fluctuations and never keep the pH meter exposed to direct sunlight.
The glass electrode should not be left out of the storage solution for prolonged intervals as the glass membrane gets dehydrated resulting in a slower response and can eventually lead to complete response failure. The electrode should not be immersed in dehydrating solutions such as sulphuric acid and ethanol.
Glass is rapidly attacked by hydrofluoric acid so never keep the electrode in HF solution as it can lead to irreparable damage to the electrode.
Avoid vibrations and shock. When using magnetic stirrers take care to maintain an adequate distance between the meter bulb and the magnetic stirrer pellet to prevent accidental breakage. A heated magnetic stirrer should never be used as it can bring about a change of the temperature of the solution.
Store sensors at ambient temperatures of 10°C to 30°C. Protective caps as well as solution storage caps provided by the supplier should be installed onto the end of the sensor when not in use.
Always keep a check to ensure that the storage solution has not evaporated.
Adopt the suggested cleaning procedures after use:
Frequently Asked Questions
Q: How often do I need to calibrate my pH tester or meter?
A: Depending on the accuracy required, once a day if several measurements are required during the day; or at least once weekly if you use 2 or 3 times per week.
Q: Why does the pH tester or meter Display "1" or show erratic reading when power is on?
A: When the electrode is held in the air and not dipped or in contact with a solution, it will display erratic readings. This is because the reference and glass electrode is in close contact, therefore the electronics cannot show a fixed reading. Dip the electrode into any solution and reading will appear.
Q: Why does the pH tester or meter take some time to get a stable reading?
A: The electrode was dry or not properly conditioned. The reference junction is possibly clogged up.
Remedy: Soak the electrode in liquid storage solution at all times when not in use.
Q: How long will a pH tester last?
A: All pH glass electrodes will age with time and temperature.
Most glass electrodes have a storage life of about 1 year. A life span of about 3 to 6 months for frequent/continuous use.
Q: What other problems are associated with measurement?
A: Temperature is important as liquid properties are affected. Therefore, a correct temperature of 25 °C for Buffer Solutions should be maintained during calibration.
