soil pH meter
Care and use guide
Contents page
Features 2
Bluelab Soil pH Meter 2
Introduction 3
Preparing for use 3
Calibration 4
Information about measuring
the pH of soils/media 6
Measuring the pH value 8
Measuring soil solution
pH value 8
Battery replacement 9
Cleaning the Bluelab
Soil pH Probe 9
Hydrating the soil pH probe 10
Storing the Bluelab Soil
pH Meter 10
Error messages 11
Technical speci cations 11
Troubleshooting guide 12
Bluelab Soil pH Probe
replacement 13
Bluelab Soil pH Probe Care 13
Product guarantee 14
Limitation of liability 14
Contact details 14
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Features
Lightweight and portable Successful pH calibration indicator
Large easy to read display 2 x AAA alkaline batteries included
Simple push button pH calibration Auto off function
Replaceable soil pH probe included Low battery indicator
Over range and under range indicators
Soil pH probe
connection
socket (BNC
fi tting)
Bluelab Soil pH Meter
Display
Dibber / Auger
Power button
Soil pH probe storage cap
The soil pH probe tip must not be allowed to dry out.
Always place the storage cap back onto the soil pH
probe after each use. Ensure the cap contains enough
Bluelab pH Probe KCl Storage Solution to cover the
probe tip.
pH unit
Successful pH
calibration indicators
Low battery
indicator
Bluelab Soil
pH Probe
Calibrate
button
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ATTENTION
If it dries, it dies!
at all times to avoid permanent damage
Keep your
soil pH probe tip wet
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1.0 Introduction
The Bluelab Soil pH Meter has two press buttons; ‘calibrate’ and power. The power button
requires a short press; release in about one second. The ‘calibrate’ button requires a long
press; hold for at least three seconds and release when the display starts fl ashing.
Turning the soil pH meter on and off
A short press of the power button will turn the soil pH meter on. The soil pH meter
automatically turns off after approximately four minutes if no buttons are pressed.
If the soil pH meter turns off before the reading is taken, short press the power
button to turn the soil pH meter on again.
2.0 Preparing for use
The following tasks must be performed before the Bluelab pH Meter is used for the
fi rst time.
Insert batteries.
See section 8.0.
Connect soil pH probe
Connect the soil pH probe to the soil pH meter
by lining up the lugs of the BNC fi ttings. Fasten
securely by pushing the pH probe connector on
and twisting one quarter turn.
Remove the storage cap
Remove the pH probe storage cap by gripping
the top of the cap and gently twisting the base
one rotation clockwise to loosen slightly. Next
slowly slide the cap off the pH probe. DO NOT
completely remove the base of the cap from the
top of the cap.
CAUTION: When the soil pH probe is not in use,
add enough Bluelab pH Probe KCl Storage
Solution to the storage cap so the probe tip is
covered. Then replace the cap and store in a
secure place.
DO NOT use RO (Reverse Osmosis), Distilled
or De-ionized water. Pure water changes
the chemistry in the reference, causing the
probe to die.
Calibrate the pH
Calibrate the soil pH meter by following the
instructions in section 3.0 of this manual.
This must be done before the
soil pH meter is used for the fi rst time.
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Inserting Twisting Attached
Attaching the
Bluelab Soil pH Probe to the Meter
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Removing soil pH
probe storage cap
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Ensure probe tip is covered by
the KCl storage solution in cap
See section 3.0
for calibration
steps
3.0 Calibration
pH calibration is required before fi rst use and then monthly to ensure readings are
accurate.
For accurate pH readings the soil pH probe is cleaned and recalibrated when:
• The reading is different to what you were expecting.
• The batteries have been removed or changed.
• The soil pH probe is replaced with a new one or is disconnected from the soil pH Meter.
• The pH calibration indicators have disappeared.
When calibrating the pH after fi rst use the soil pH probe needs to be cleaned. See soil
pH probe cleaning in section 8.0. The soil pH probe does not need to be cleaned for
initial calibration.
For best pH calibration
pH reading accuracy is dependant on the accuracy and age of the calibration
solutions used, and use and cleanliness of the soil pH probe tip.
• Ensure the soil pH probe has been cleaned and rinse the soil pH probe tip with clean
water between calibration solutions to reduce contamination of the pH solutions.
• Only fresh uncontaminated solutions should be used.
• Calibrate the pH at the same temperature as the solution to be measured.
• ALWAYS calibrate the soil pH probe with pH 7.0 then pH 4.0 or pH 10.0.
The pH calibration involves cleaning the soil pH probe tip and then calibrating in
TWO SOLUTIONS.
If a reading below pH 7.0 is expected, use pH 7.0 and pH 4.0 calibration solutions.
If a reading above pH 7.0 is expected, use pH 7.0 and pH 10.0 calibration solutions.
Follow the steps below for soil pH meter calibration.
Storage and use of calibration solutions
• Always place the lid back onto the bottle after use or evaporation will occur rendering
the solution useless.
• Store in a cool place.
• DO NOT measure directly into the bottle. Tip a small amount into a clean container
and discard after use.
• Never add water to solutions.
pH reading accuracy is dependant on the
accuracy and age of the calibration solutions
used, and use and cleanliness of the soil pH
probe tip.
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3.0 Calibration cont.
To calibrate the pH
Clean soil pH probe tip.
See section 8.0 (the soil pH probe does not
require cleaning before the fi rst use).
pH 7.0 calibration
a) Turn soil pH meter on. Rinse soil pH probe
tip in fresh water, shake off excess water and
place in a pH 7.0 calibration solution. Wait for
at least one minute or longer if required for
reading to stablize to a constant value.
b) Long press the ‘calibrate’ button. When the
display shows CAL release button.
pH 7 indicator is displayed indicating
a successful pH 7 calibration.
The pH 4 indicator will now fl ash
indicating pH 4.0 or pH 10.0
calibration is now required.
c) If Err appears during the calibration process
see section 9.0.
d) The soil pH meter must be calibrated to two
points. If after an hour the soil pH meter has
not been calibrated with a second calibration
point the calibration indicators disappear and
the soil pH meter reverts to an uncalibrated
state. Calibration is required.
pH 4.0 / 10.0 calibration
a) Rinse the pH probe tip in fresh water, shake
off excess water and place the
pH probe tip in either pH 4.0 or pH 10.0
calibration solution.
b) Wait for at least one minute for reading to
stabilize to a constant value.
c) Long press the ‘calibrate’ button. When the
display shows CAL release button.
pH 7 / pH 4 is displayed
or pH 7 / pH 10 is displayed
d) The pH meter is now calibrated and ready
for use.
e) After 30 days, the calibration indicators
disappear to let you know calibration is required.
Store the soil pH probe
Add enough Bluelab pH Probe KCl Storage Solution
into the probe storage cap to fully submerge the
soil pH probe tip. Place storage cap on probe.
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clean the soil pH probe
pH 7.0
calibration
solution
rinse in tap water
pH 4.0 or
pH 10.0
calibration
solution
Successful pH 7
and pH 4 calibration
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Ensure probe tip is covered by
the KCl storage solution in cap
4.0 Information about measuring the pH of soils/media
pH is the measurement of the hydrogen ion concentration (H+) - acidity and
its opposite, alkalinity. Neutral pH is 7.0 pH. Acidity measures below seven
pH (7.0 pH) with alkalinity measuring above it (7.0 pH). See chart below.
In soils or growing media, pH strongly infl uences the availability of nutrients and the
presence of microorganisms in the soil.
Certain plants require a particular pH range to enable the required nutrients to be consistently
available to the plant. If the solution is too acidic or too alkaline it can cause “lock up” – a
situation which restricts certain elements essential for growth from being absorbed by the
root structure. This in turn reduces plant health and performance. Defi ciencies in the required
elements become apparent in plant growth and can lead to crop failure.
Low soil pH causes aluminium and manganese toxicity in plants and reduces the availability
of soil phosphorus. High soil pH also reduces soil phosphorus availability and reduces micro
nutrients such as zinc and boron to plants.
The chart below shows how nutrient pH levels infl uence the uptake of certain elements.
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Recommended pH range
for plants grown in:
Solution
5.5 - 6.3
can be plant specifi c
Soil
6.2 - 7.2
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4.0 Information about measuring the pH of soils/media cont.
Taking pH measurements of soils with an electronic meter is indicative
rather than absolute.
The following factors are outside the control of any soil pH meter, so to minimise
their effect on the accuracy of the pH measurement you should consider the
following precautions:
Moisture level/raw water
If the sample you are wishing to measure is dry, add RO water or distilled water to
moisten. Ideally wait 24 hours before you take a measurement.
NOTE: If you add tap water, you will infl uence the soil pH reading based on the pH of the
tap water.
Calibration of the soil pH meter and cleanliness of the soil pH probe tip
Calibrating the soil pH meter at least monthly will ensure accurate readings. Cleaning the
soil residue from the probe tip and storing the soil pH meter in a clean moist state will
provide reliable readings as well as prolonging the probes life.
Sample selection
For fi eld testing, remove the top 5 - 10 cm / 2 - 4” of the top of the soil. Samples are
taken approximately 15 - 20 cm / 6 - 8” down into the substrate and from various areas,
then an average of the readings is used.
For container grown plants, it is recommended to check the pH level of the substrate
prior to planting.
Factors affecting pH in the soil or media:
Soil type
Soils formed under high rainfall conditions (e.g. Eastern USA) are more acidic than those
formed under dry conditions (e.g. Western USA).
Growth stage of the plant
Uptake and requirements of particular elements change as the plant progresses through
it’s growing cycle. Recording pH level data to create a history is valuable.
Applications and types of fertilizers
Applications and types of fertilizers can alter the pH level signifi cantly. The time at which
you take the reading is important. Evaluate the brand of fertilizer to see if it is altering the
pH in the wrong direction.
Applications of sprays
As sprays can soak into the soil/media, a change to the pH level could result.
Soil/media temperature
High temperature soils may have a high concentration of CO
2
. The higher the
concentration of carbon dioxide pressure results in more carbonic acid which lowers pH.
pH range for soil crops
The recommended pH range for soil crops is 6.2 - 7.2, but this is plant specifi c.
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5.0 Measuring the pH value
Once the Bluelab Soil pH Meter has been set up and calibrated, using it to measure a pH value
involves using the Bluelab Soil pH Probe, the green dibber/auger, a soil/media sample and
button functions. NOTE: The soil pH probe tip must not have dried out. If it has dried, soak the soil
pH probe in tap water for one hour prior to taking a measurement.
Remove the top 5 cm / 2 in. from the surface of the sample area.
Insert the dibber/auger into the sample to a depth of about 20 cm / 8 in. and remove.
If the soil/media is dry, moisten with a small amount of distilled water.
Remove the storage cap and insert the soil pH probe to the same depth ensuring the
probe end makes proper contact with the soil.
Turn the soil pH meter on.
Wait for the reading displayed on the soil pH meter to stablize to a constant value. This
can take up to four minutes. Record the reading.
Remove the soil pH probe from the soil/media and wash the soil pH probe tip under fresh
running water (not distilled) to remove any remaining soil residue.
Repeat the procedure in different locations and take the average of the measured data as
the pH level is representative of the sample area.
If the soil pH meter turns off while taking a measurement, simply press the power button
to turn the soil pH meter back on and continue with your measurement.
Store the soil pH probe between measurements. See section 10.0.
6.0 Measuring soil solution pH value
The greatest source of error in soil analysis comes during sample collection. An effort should be
made to ensure each sample properly represents the area being sampled.
• The readings taken with this method could be higher than those taken by other methods
• Consistency of the method used is important to be able to compare sets of results
• The accuracy of this method cannot be guaranteed because of the variables involved
• The results should be viewed as ‘indicative’ rather than ‘absolute’
Collection of sample
Sample in a zig-zag pattern across the required area.
Remove 15 mm / 5/8 in. of top soil before sampling at a depth of 150 mm / 6 in.
Mix all collected samples together thoroughly.
Allow to dry in the air or in an oven at 40 °C / 104 °F.
Weigh out 20 g / 0.7 oz of the collected soil into a 150 ml / 5 fl oz plastic sample jar.
Sample preparation
Add 100 ml / 3 fl oz of distilled or deionised water, screw lid on tightly.
Shake continuously for 5 minutes. Leave overnight and shake again the next morning.
Allow to settle for 15 minutes after shaking and strain sample into clean measuring cup.
Take pH readings as follows:
Remove the storage cap and insert the soil pH probe tip into the soil solution sample.
Turn the soil pH meter on.
Wait for the reading displayed on the soil pH meter to stablize to a constant value. This
can take up to four minutes. Record the reading.
Remove the soil pH probe from the soil solution and wash the soil pH probe tip under
fresh running water (not distilled) to remove any possible soil residue.
If the soil pH meter turns off while taking a measurement, simply press the power button
to turn the soil pH meter back on and continue with your measurement.
Store soil pH probe between measurements
See section 10.0.
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7.0 Battery replacement
Batteries are replaced in the Bluelab Soil pH Meter when the low battery indicator
appears on screen. The low battery indicator remains on and the Bluelab Soil pH
Meter continues to operate until the batteries die or are replaced.
Open battery compartment by sliding the back cover down and
insert 2 x AAA batteries as shown on the battery holder. Slide
cover back on. NOTE: Alkaline batteries are recommended.
IMPORTANT: Check the batteries at least once every six
months for signs of deterioration, rusting or swelling.
If signs of deterioration are found, clean battery holder
contacts and replace batteries.
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8.0 Cleaning the Bluelab Soil pH Probe
To ensure accurate readings the soil pH probe tip needs to be rinsed in water after each
use and cleaned prior to calibration using the following instructions.
The storage cap must always be put back on after cleaning. Always ensure it contains
enough Bluelab pH Probe KCl Storage Solution to cover the probe tip.
Remove storage cap from soil pH probe.
Hold the top of the storage cap, twist the cap to
loosen then remove.
Rinse soil pH probe tip under fresh tap water.
Never use RO (Reverse Osmosis), Distilled or
De-ionized water.
Fill a small plastic container with clean tap water.
Add a small amount of Bluelab pH Probe Cleaner
or mild detergent (dishwashing liquid).
Gently stir the probe tip in the mixture.
Ensure that you do not ‘knock’ the soil pH probe
on the side of the container as this may cause
damage to the probe.
Rinse well under fresh running water to remove all
traces of the detergent mixture.
If the probe tip requires removal of heavy
contamination: Gently brush around the
glassware with a few drops of Bluelab pH Probe
Cleaner or mild detergent (dishwashing liquid) and
a soft toothbrush.
Rinse well under fresh running tap water to
remove all traces of the detergent mixture.
Calibrate soil pH probe after cleaning, see
section 3.0 After calibration, store soil pH probe
in the storage cap, ensuring there is enough KCl
Storage Solution to cover the probe tip.
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Battery
cover
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10.0 Storing the Bluelab Soil pH Meter
Store the soil pH meter in a cool, dry and clean place when not in use.
Keep out of direct sunlight.
Keep soil pH meter out of direct sunlight to prevent irreparable damage to the LCD
reading display.
The soil pH meter is not waterproof but will withstand occasional water splashes.
If the soil pH meter is splashed, wipe dry as soon as possible.
Remove batteries if the pH Meter is to be stored for a prolonged period.
Remove pH probe if storing the pH Meter without use for longer than two to three
weeks and check regularly that the pH probe tip has not dried out.
When storing the soil pH probe, the soil pH probe tip must be kept moist.
To prepare the soil pH probe for storage, add enough Bluelab pH Probe KCl Storage
Solution to the storage cap so the probe tip is covered. Then replace the cap and
store in a secure place. DO NOT use RO (Reverse Osmosis), Distilled or De-ionized
water. Pure water changes the chemistry in the reference, causing the probe to die.
9.0 Hydrating the soil pH probe
Hydrate the soil pH probe in Bluelab pH Probe KCl Storage Solution when:
• the probe tip has not always been stored in KCl storage solution, to improve
the reading response speed.
• the probe tip has been accidentally allowed to dry out
Never use RO (Reverse Osmosis), De-ionized or Distilled water.
Pure water changes the chemistry in the reference, causing the probe to die.
Loosen, then remove the storage cap.
Place the soil pH probe upright in a plastic
container.
Clean the soil pH probe tip.
Ensure the probe tip is cleaned before
hydrating. See section 8.0 for instructions.
Add enough Bluelab pH Probe KCl
Storage Solution to a plastic container to
submerge the soil pH probe tip.
Leave to soak for at least 24 hours.
After hydration, always calibrate the soil pH
probe to ensure accuracy, see section 3.0.
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Bluelab pH Probe KCl
Storage Solution
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11.0 Error messages
An error message will only appear following pH calibration failure.
‘Err’ will be displayed for a few seconds then the display will show the previous
reading. Successful pH calibration indicators will disappear. The Bluelab Soil pH
Meter is in an uncalibrated state, therefore recalibration is required. See causes
of Error messages below.
Possible causes for an ‘Err’ message:
• Calibration solutions contaminated
• Wrong solutions used
• pH probe contaminated
• pH probe not properly attached
• pH probe worn out or damaged
• Calibrate to pH 7.0 FIRST then to pH 4.0/10.0
12.0 Technical speci cations
pH
Measurement range 0.0 - 14.0 pH
Resolution 0.1 pH
Accuracy at 25 °C/77 °F ±0.1 pH
Calibration Two point pH 7.0 and pH 4.0 or pH 10.0
Temperature compensation Not applicable
Operating environment
0 - 50 °C
32 - 122 °F
Power source 2 x AAA alkaline batteries
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13.0 Troubleshooting guide
Trouble Reason Correction
pH reading inaccurate
Contaminated soil pH
probe / glassware not
clean.
Clean soil pH probe (see section
8.0); then calibrate.
Wick contaminated,
blocked or dry.
Hydrate probe in KCl storage
solution for 24 hours, see section
9.0. Do not measure proteins or
oils with this unit. Replace unit.
Incorrect pH calibration.
Ensure calibration solutions are
accurate. Replace if in doubt.
Wait longer for readings to
stabilize before calibrating to a
constant value.
pH calibration unreliable.
Calibrate soil pH probe
(see section 3.0).
soil pH probe damaged
or old.
Replace soil pH probe.
pH reading does not
change from solution
to solution
Broken glass bulb,
tube or connector.
Check soil pH probe for damage.
Replace probe.
Displays low
battery indicator
Insuffi cient power to take
a reliable reading.
Replace the batteries.
DO NOT use rechargeable
batteries.
No display
Batteries dead or
inserted incorrectly.
Check batteries are inserted
correctly. Replace if necessary.
Display shows ‘Err’
Problem with pH
calibration.
See error message descriptions in
section 11.0 of this document.
Or
Ur
While in pH mode
Over range pH.
Under range pH.
Solution > 14.0 pH.
Solution < 0.0 pH.
Check pH probe connection.
pH probe could be faulty.
pH meter could be wet inside.
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Bluelab Soil pH Probe replacement
The Bluelab pH Probe is the only part of the Bluelab
Soil pH Meter that requires replacing.
Soil pH probes do not last forever. They age
through normal use and will eventually fail.
To ensure you receive a long life from your soil
pH probe, please read the instructions provided
with it.
When the time comes to replace your Bluelab
Soil pH Probe all you have to do is order a
replacement from your supplier!
Bluelab Probe Care - pH
The instrument is only as accurate as
the probe is clean!
Probe cleaning is one of the most
important parts of owning and operating
any Bluelab meter, monitor or controller.
If the probe is contaminated (dirty) it affects
the accuracy of the reading displayed.
Bluelab Probe Care Kit - pH contents:
› Cleaning instructions inside box lid
› 500ml pH4.0 and pH7.0 calibration
solutions
› Plastic cups
› Bluelab pH Probe Cleaner
› Toothbrush (probe cleaning instrument)
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Bluelab pH Probe KCl Storage
Solution
The perfect solution to store and hydrate
your Bluelab pH products.
Bluelab pH Probe KCl Storage Solution is designed
to increase response time and maximize the life of
Bluelab pH pens and pH probes.
For best results, use the KCl solution to store the pH pen/
probe after use and hydrate monthly.
Instructions are on the label of the bottle.
Use Bluelab pH Probe KCl Storage Solution with:
› Bluelab pH Pen
› Bluelab Soil pH Pen
› Bluelab pH Probes
› Bluelab Soil pH Probes
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Bluelab Soil pH Meter product guarantee
Bluelab Corporation Limited guarantees this product for a period of
5 years (60 months) from the date of sale to the original purchaser.
(This guarantee does not cover the Bluelab Soil pH Probe. The Bluelab
Soil pH Probe is covered by a separate 6 month guarantee.)
The product will be repaired or replaced should it be found faulty due to
component failure, or faulty workmanship. The faulty product should be
returned to the point of purchase.
The guarantee is null and void should any internal parts or fi xed external parts be tampered
with or altered in any way, or should the unit have been incorrectly operated, or in any way be
maltreated. This guarantee does not cover reported faults which are shown to be caused by
any or all of the following: Contaminated measuring tip (see instruction manual for cleaning
instructions), fl at or damaged batteries or batteries that have been incorrectly inserted, or
damaged battery contacts or connections caused by incorrect battery replacement, or ingress
of moisture into the meter case.
NO RESPONSIBILITY will be accepted by Bluelab or any of its agents or resellers should any
damage or unfavourable conditions result from the use of this product, should it be faulty or
incorrectly operated.
Register your guarantee online at www.getbluelab.com
Limitation of Liability
Under no circumstances shall Bluelab Corporation Limited be liable for any claims,
losses, costs and damages of any nature whatsoever (including any consequential
loss) that result from the use of, or the inability to use, these instructions.
To watch instruction videos, visit our online video library:
vimeopro.com/bluelab/videos
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If you need assistance or advice - we’re here to help you.
Phone: +64 7 578 0849 Fax: +64 7 578 0847
Email: support@getbluelab.com
Looking for specifi cations or technical advice?
Visit us online at www.getbluelab.com
Bluelab Corporation Limited
8 Whiore Avenue, Tauriko Industrial Park
Tauranga 3110, New Zealand
Instruction Manual English METSOILPH_V02_090813
© Copyright 2011, all rights reserved, Bluelab Corporation Limited
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