PLANT!T – pH Meter
- The LCD dual display shows pH and temperature readings
- Calibration is easy with a one-touch autocalibration and can give up to a 3 point calibration
- The meter is IP65 waterproof rated
- Includes safety lid
- Hold reading function
- Highly accurate readings
- Best value for the price
To grow plants successfully, particularly in hydroponics. It is necessary to monitor and adjust the pH of your nutrient solution on a regular basis. In general, plants are grown in hydroponics like a pH of approximately between 5.5 and 6.5 (plant species dependent) with a little bit of variation within this range. This is because plants can only absorb certain nutrients at a pH close to 5.5 and others at a pH closer to 6.5.
If your nutrient solution strays out of this optimum range for too long, your plants will not be able to absorb all the nutrients that they need and will become deficient, leading to slowed growth and eventually sickness. To avoid pH problems, and the plant problems that it can cause, it is wise to check and adjust the pH of your nutrient solution very regularly (every day if possible). Soil-grown plants tend to like a pH of around 6.5. A good way of finding out the pH of your soil is to test the run-off water which comes out of the bottom of the pot when you water.
The PLANT!T Digital pH meter is reliable and easy-to-use. Small and lightweight, it is ideal for any grow room. This is a great value reliable digital ph tester pen for testing the ph levels of a liquid.
Multi-purpose suitable for water, hydroponics, nutrients, aquariums, swimming pools etc.
The pH meter is specially designed for testing the pH level of nutrient solutions. Just dip the sensor into test solution, stir and wait, then read a stable reading in about 20 seconds.
The unit is water resistant, allowing easy washing. Even if the meter is accidentally dropped into the water, it will remain afloat so as to enable immediate retrieval without damaging the electronics.
The energy saving feature shuts off the tester when it is not in use. The unit also displays a low battery symbol to warn you before it degrades the accuracy of important readings. It has digital calibration at the push of a button.
Conversions: 1 Teaspoon = 5mL | 1 Tablespoon = 15 mL | 1 Ounce = 30mL | 1 Cup = 240 mL
What does the pH measure?
The pH value of a substance is directly related to the ratio of the hydrogen ion [H+] and the hydroxyl ion [OH-] concentrations.
The quantitative information provided by the pH tester expresses the degree of the activity of an acid or base in terms of hydrogen ion activity.
- If the H+ concentration is greater than OH-, the material is acidic; i.e., the pH measurement is less than 7.
- If the OH- concentration is greater than H+, the material is basic, with a pH value greater than 7.
- If equal amounts of H+ and OH- ions are present, the material is neutral, with a pH of 7.
Acids and bases have free hydrogen and hydroxyl ions, respectively. The relationship between hydrogen ions and hydroxyl ions in a given solution is constant for a given set of conditions, either one can be determined by knowing the other.
How to measure pH?
A rough indication of pH can be obtained using pH papers or indicators, which change colour as the pH level varies. These indicators have limitations on their accuracy and can be difficult to interpret correctly in coloured or murky samples. More accurate pH measurements are obtained with a digital pH meter. A pH tester system consists of three parts: a pH probe, a reference pH electrode, and a high input impedance meter.
The pH electrode can be thought of like a battery, with a voltage that varies with the pH of the measured solution. The pH probe is a hydrogen ion sensitive glass bulb, with a millivolt output that varies with the changes in the relative hydrogen ion concentration inside and outside of the bulb.
The reference electrode output does not vary with the activity of the hydrogen ion.
The pH electrode has very high internal resistance, making the voltage change with pH difficult to measure. The input impedance of the pH meter and leakage resistances are therefore important factors.
The pH meter is basically a high impedance amplifier that accurately measures the minute electrode voltages and displays the results directly in pH units on either an analogue or digital display.
In some cases, voltages can also be read for special applications or for use with ion-selective or Oxidation-Reduction Potential (ORP) electrodes.
pH electrodes are constructed from a special composition glass which senses the hydrogen ion concentration. This glass is typically composed of alkali metal ions. The alkali metal ions of the glass and the hydrogen ions in solution undergo an ion exchange reaction, generating a potential difference.
In a combination pH probe, the most widely used variety, there are actually two electrodes in one body. One portion is called the measuring pH electrode, the other the reference electrode. The potential generated at the junction site of the measuring portion is due to the free hydrogen ions present in solution.
The potential of the reference portion is produced by the internal element in contact with the reference fill solution. This potential is always constant. In summary, the measuring pH electrode delivers a varying voltage and the reference electrode delivers a constant voltage to the meter.
he voltage signal produced by the pH probe is a very small, high impedance signal. The input impedance requires that it be interfaced only with equipment with high impedance circuits.
pH electrodes are available in a variety of styles for both laboratory and industrial applications. All are composed of glass and are therefore subject to breakage.
Electrodes are designed to measure mostly aqueous media. They are not designed to be used in solvents, such as CCI4, which does not have any free hydrogen ions.
The pH electrode, due to the nature of its construction, needs to be kept moist at all times. In order to operate properly, glass needs to be hydrated.
Hydration is required for the ion exchange process to occur. If a pH sensor should become dry, it is best to place it in some tap water for a half hour to condition the glass.
pH electrodes have junctions which allow the internal fill solution of the measuring electrode to leak out into the solution being measured. This junction can become clogged by particulates in the solution and can also facilitate poisoning by metal ions present in the solution.
If a clogged junction is suspected it is best to soak the sensor in some warm tap water to dissolve the material and clear the junction. pH testers should always be stored in a moistened condition. When not in use it is best to store the electrode in either buffer 4.0 or buffer 7.0. Even if an electrode is not used it still ages. On the shelf, the pH probe should last approximately a year if kept in a moistened condition.
Electrode demise can usually be characterized by a sluggish response, erratic readings or a reading which will not change. When this occurs an electrode can no longer be calibrated. pH electrodes are fragile and have a limited lifespan. How long an electrode will last is determined by how well the probe is maintained and the pH application.
The harsher the system, the shorter the lifespan. For this reason, it is always a good idea to have a back-up pH sensor on hand to avoid any system downtime.
Calibration is also an important part of electrode maintenance. This assures not only that the electrode is behaving properly but that the system is operating correctly.
pH meter calibration
pH electrodes are like batteries; they run down with time and use. As an electrode age, its glass changes resistance. This resistance change alters the electrode potential. For this reason, electrodes need to be calibrated on a regular basis.
Calibration in pH buffer solution corrects for this change. Calibration of any pH equipment should always begin with buffer 7.0 as this is the “zero point.” The pH scale has an equivalent mV scale. The mV scale ranges from +420 to -420 mV. At a pH of 7.0, the mV value is 0. Each pH change corresponds to a change of ±60 mV. As pH values become more acidic the mV values become greater.
For example, a pH of 4.0 corresponds to a value of 180 mV. As pH values become more basic the mV values become more negative; pH=9 corresponds to -120 mV. Dual pH calibration using buffers 4.0 or 10.0 provides greater system accuracy.
Here is a general method for most digital pH meters. Some pH testers require slightly different techniques. Please read the instructions for their particular procedures.
- The temperature setting on the meter must correspond to the temperature of the buffers used, or an automatic temperature compensator must be employed.
- Turn pH meter to “pH” or “ATC” if automatic temperature compensation is used.
- Place clean electrode into fresh, room temperature pH 7.00 buffer.
- Adjust the pH reading to exactly 7.00 using the ZERO OFFSET, STANDARDIZED or SET knob.
- Rinse the electrode with distilled or deionized water. (This would be the procedure for a one-point calibration. Continue through step 8 for a two-point calibration.)
- Place electrode into the second buffer, either pH 4.00 or pH 10.00.
- Adjust the pH reading to display the correct value using the SLOPE, CALIBRATE, or GAIN controls (coarse adjust).
- Adjust the pH reading to read the correct value using the SLOPE knob (fine adjust).
Buffers are solutions that have constant pH values and the ability to resist changes in that pH level. They are used to calibrate pH measurement systems (electrode and meter). There can be small differences between the output of one electrode and another, as well as changes in the output of electrodes over time. Therefore, the system must be periodically calibrated. Buffers are available with a wide range of pH values, and they come in both premixed liquid form or as convenient dry powder capsules. Most pH testers require calibration at several specific pH values. One calibration is usually performed near the isopotential point (the signal produced by an electrode at pH 7 is 0 mV at 25°C), and a second is typically performed at either pH 4 or pH 10. It is best to select a buffer as close as possible to the actual pH value of the sample to be measured
“Seems to work OK as it gives different readings in different soils. Whether the readings are accurate or not I wouldn’t know but it gives an indication whether the soil is alkaline, acid or very acid, dry or wet, well lit or not.”
“This gadget has given me answers regarding the stunted growth of some flowers & that it’s not entirely my fault. I didn’t know until now, that the soil was too alkaline! At least I know which flowers to plant next season that can tolerate a bit better.”
“ Took it out of the package as soon as it arrived, put it in the planter and was amazed how fast it worked. Great buy, thanks.“
Why Choose PLANT!T
PLANT!T® offers a range of products for your indoor and outdoor growing needs. New from PLANT!T® is a range of hydroponic growing systems designed to help you gain optimum results and success.
The PLANT!T® range of hydroponic systems comprises of the PLANT!T® Gemini – a recirculating hydroponic system (a 1 plant system), the PLANT!T® Aeros – an aerated Deep Water Culture hydroponic system (available in 1 plant or 2 plant options and in a 4 plant recirculating option), the PLANT!T® titan, a table-based flood & drain hydroponic system (available in 4 sizes) and the PLANT!T® atlas, a table-based recirculating drip irrigation system (available in 12L pot, 18L pot and dripper only options).
All PLANT!T® hydroponic systems have been designed to the highest specifications to ensure that not only do they perform with excellent results, but they also look stylish too. The range is easy to set up, operate and maintain. PLANT!T® hydroponic systems are suitable for all types of a gardener, including commercial growers, keen hobbyists and even those new to gardening.
All of the PLANT!T® hydroponic systems are designed and manufactured for quick and easy assembly.
With PLANT!T® hydroponic systems, growing bigger and better plants has never been so easy.
Why choose PLANT!T® hydroponic systems:
Stylish design to utilise any given growing space
Manufactured using quality materials
Where to use PLANT!T® hydroponic systems
These systems can be used in commercial greenhouses, nurseries, schools, offices, greenhouses, sheds and at home. They are quiet running and can be placed anywhere in the home such as the kitchen, dining room, hallway, living room or conservatory.