Spectrum Technologies 2305G User manual

Cardy Nitrate
NO3–Meter
PRODUCT MANUAL
Item 2305G

2
Contents
Introduction …………………………….. 3
Meter Components and Functions …….. 4
Handling Precautions ……….……………. 6
Calibrating Solutions …………………….. 8
Calibration ……………………………….. 9
Measurement Procedure …...…………….. 12
Special Setting Modes …......…………….. 14
Replacing the Sensor ...................…………. 18
Installing and Replacing Batteries ….…….. 19
Preparing Soil Samples ....................…….. 20
Collecting Tissue Sap ...........………....….. 23
Preparing Soil-less Media ............…..…….. 24
Specifications …………………………….. 26
Soil Test Kit Accessories …………….….. 27
Sufficiency Levels ....…………………….. 28
Warranty …………….……………………. 34
This manual will familiarize you with the features and
operation of your Cardy Nitrate meter. Please read this
manual thoroughly before using your meter. For customer
support or to place an order, contact Spectrum
Technologies, Inc between 7:30 a.m. and 5:30 p.m. CST.
Phone: [phone] or [phone]
Fax: [phone]
E-mail: [email protected].
Website: www.specmeters.com

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Congratulations on the purchase of your Cardy Nitrate
(NO3-) meter. This manual describes how to use your
Cardy meter and how to keep it working accurately for
many years. Read it thoroughly in order to make effective
use of your meter.
Nitrogen is one of the most important elements required
for plant growth. It is a key component in chlorophyll, the
pigment in plants that harnesses the sun’s energy to con-
vert CO2into carbohydrates and makes plants green.
Tools that provide increased management of N offer sig-
nificant economic benefits to plant growers of all types.
In addition, applying just the right amount of nitrogen at
the right time can help safeguard the environment by re-
ducing the amount of residual soil nitrate
(NO3-) available to leach into ground water
This self-contained, waterproof, digital meter delivers
high quality answers to nitrate level questions in soils,
plants, and water- based solutions. The replaceable pen-
type sensor makes the measurement of small samples
much more convenient. When replacement of the sensor
is required, the sensor cartridge snaps in and out of the
meter at a touch.
The readout of the measurement value is an LCD display.
It a has a total display range of 14 - 1400 ppm NO3--N.
The display can be set to readout in units of nitrate (NO3-)
or nitrate-nitrogen (NO3--N).
Introduction

4
Meter Components
And Functions
No. Name Description
1 Flat sensor Consists of a liquid junction (electrode
A) and response membrane (electrode B).
Both electrodes must be covered by sam-
ple to enable accurate measurement.
2 Light shield
cover Cover used to shield sensor from light. Because the sensor is affected by light,
attach the light shield cover before start-
ing measurement.
3 Lithium
batteries CR2032

5
No. Name Description
4 MEAS
button Used during measurement. Press the button for ½ second to evaluate
the stability of the measured value.
The screen will lock onto a stable
value. If this button is pressed for 5
seconds, the meter will go into the
special setting mode (p. 14)
5 ON/OFF
button Press and hold for at least 2 seconds to turn meter ON or OFF.
6 CAL
button Press and hold for at least 2 seconds to calibrate the meter.
7 Waterproofing
gasket Provides waterproof seal for meter.
8 MEAS
icon Flashes during calibration and lights steadily when meter locks onto a
measurement.
9 CAL
icon Flashes during measurement and lights steadily when calibration is fin-
ished.
10 Battery alarm
icon Lights when batteries are low in power and need to be replaced.
12 Stability
icon Lights only when the measured value has stabilized.
13 Display Flashes when the measurement is
out of range. When Hi is displayed,
the result is too high. Dilute the sam-
ple and take measurement again.
14 Measurement
unit display The default setting is “NO3-”. See
“Special Setting Modes” (p. 16) for
instructions to change modes.
11 Temperature
alarm icon Flashes when the measuring envi- ronment temperature is out of range
(not between 5º and 40ºC).

6
• When using the meter for the first time, or after sev-
eral weeks of inactivity, the sensor may be slow to re-
spond. Put some reference solution on the sensor and
wait 10 to 60 minutes before switching the meter on.
Handling Precautions
• Neither the meter nor sensor is waterproof by itself.
The sensor must be securely mounted on the meter
before use.
• The sensor is made of PVC and may get scratched if
not handled with care.
• Do not leave the meter in areas of direct sunlight or
high temperature/humidity
• Do not clean the meter with organic solvents.
• Never drop the meter or apply exces-
sive force to it.

7
• Sensor B is made of PVC.
Because the PVC’s plasti-
cizer may seep into the fluid
being measured, never drink
any fluid that has come in
contact with the sensor.
• The batteries provided with
the meter are for monitoring
and may have a short life.
• When replacing batteries, replace both at once.
• Never dispose of batteries in an open flame or attempt
to recharge them. Keep used batteries out of reach of
children.
• Replace the batteries when the low voltage alarm icon
illuminates. When the voltage is low, you may not be
able to turn the meter on.
• The sensors cannot be repaired. They must be re-
placed when they get damaged or when performance
deteriorates due to age.
• Measurement of organic solvents, oils, adhesives, ce-
ment, alcohols or concentrated acids (pH less than 2)
will shorten the sensor’s life.
• Some sample types (such as oily plant sap) may not
yield stable values.
• To ensure a waterproof seal, check that the water-
proofing gasket is not scratched or dirty and is prop-
erly seated in the groove.
• Wash off any calibration solution that comes into con-
tact with hands or exposed skin. If fluid gets in the
eyes, rinse them immediately and see a doctor.
• White powder may appear on sensor electrode A (the
liquid junction) when using the meter in low-humidity
environments. Liquid may appear on the electrode in
high humidity environments. The appearance of pow-
der or liquid is normal. Simply wash it off with water
before using the meter.

8
Calibrating Solutions
NO3
-(nitrate) versus NO3 --N (nitrate-nitrogen)
The sensor of the Cardy meter measures NO3-nitrate ion ac-
tivity similar to the way a pH sensor measures H+ion activ-
ity. Decide whether you desire the meter LCD display to
express the sample concentration as NO3-nitrate or NO3--N
nitrate-nitrogen. (Note: this is similar to referencing length
as 6 in. or ½ ft.). Laboratory analysis and university guide-
lines are generally expressed as NO3--N nitrate-nitrogen.
To convert NO3--N nitrate-nitrogen to NO3– nitrate:
multiply or divide
NO3--N x 4.42 = NO3– NO3--N / .226 = NO3–
Therefore:
2000 ppm NO3– nitrate = 450 ppm NO3--N nitrate-nitrogen
150 ppm NO3– nitrate = 34 ppm NO3--N nitrate-nitrogen
The following table shows the concentrations of the various
calibration standards in each unit of measurement.
Description ppm NO3
- ppm NO3 --N
#2311 450 ppm NO3--N * 2000 450
#2312 34 ppm NO3--N *150 34
#2336 450 ppm NO3--N ** 2000 450
#2334L 34 ppm NO3--N ** 150 34
* For use with plant sap, water and nutrient solutions.
** For use with soil samples (contains aluminum sulfate).

9
Calibration
Selecting the Calibration Mode.
The meter is shipped with the meter in 2-point calibration
mode. The calibration mode can be changed as follows
(see also “Special Settings Modes” , p. 14)
1. With the meter on, press and hold
the MEAS button for at least 5 sec-
onds to enter the special setting
mode. When all the LCD elements
illuminate, release the MEAS but-
ton so the number 1 appears. If the button is held too
long, the LCD will display the word “Unit”. In this case,
press and hold the MEAS button to get back into meas-
urement mode and repeat this step.
2. Press and hold the CAL button
until the CAL icon and the number
3 appear. If you pass number 3,
press and hold the CAL button until
it cycles around to number 3
3. Press the MEAS button to dis-
plays the current calibration mode
(1- or 2-point). Press the CAL but-
ton until the desired number of cali-
bration points appears (It will tog-
gle between 1 and 2).
4. Press the MEAS button to save the calibration mode.
The meter will return to standard measurement mode.

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One-Point Calibration (ppm NO3-- N mode)
1. Press and hold the ON/OFF button
for, at least, two seconds to power the
unit on.
2. Open the light shield cover and add
enough of the 450 ppm NO3-- N refer-
ence solution to cover the space be-
tween electrodes A and B. Rinsing the
sensor pad with reference solution be-
forehand will increase the accuracy of
the calibration.
3. Close the light shield cover
and press the CAL button un-
til the CAL icon flashes (a
minimum of 2 seconds).
4. When the calibration has been finalized, the CAL icon
will stop flashing. The reference solution concentration
will be displayed along with the icon. The meter has
not properly calibrated if the CAL icon remains flashing
or if the ERR symbol is displayed on the LCD. In this
case, confirm you have used the correct calibration solu-
tion, wash the sensor thoroughly and try to re-calibrate the
sensor.
5. Wash the sensor with tap water and remove any adher-
ing droplets before taking measurements.
6. Press the MEAS button to return to measurement mode.

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Two-Point Calibration (ppm NO3-- N mode)
1. Press and hold the ON/OFF button for,
at least, two seconds to power the unit on.
2. Add enough of the 34 ppm NO3--N
reference solution to cover the space
between electrodes A and B. Close
the light shield cover and press the
CAL button until the CAL icon
flashes (a minimum of 2 seconds).
3. When the first calibration has been finalized, the CAL
icon will stop flashing. The first calibration must be final-
ized before proceeding to the second calibration.
4. Repeat step 2 with the 450 ppm NO3--N reference solu-
tion.
5. When the second calibration has been finalized, the
CAL icon will stop flashing and the reference solution
concentration will be displayed. The meter has not prop-
erly calibrated if the CAL icon remains flashing or if
“ERR” is displayed on the LCD. In this case, confirm you
have used the correct calibration solution, wash the sensor
thoroughly and try to re-calibrate the sensor.
If the two calibrations fail but the displayed reference so-
lution concentration is correct, the sensor should be re-
placed.
6. Wash the sensor with tap water and remove any adher-
ing droplets before taking measurements.
7. Press the MEAS button to return to measurement
mode.

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Measurement procedure
Measurement on a flat surface
Important: Do not make measurements with the
meter (sensor) in direct sunlight.
1. Open the light shield cover and
add enough of the sample to cover
the space between electrodes A and
B.
2. Close the light shield cover
3. When the stability icon appears,
the LCD will display the current ni-
trate concentration. To lock in a read-
ing, press the MEAS button. The
MEAS icon will flash to indicate that
measurement has begun.
4. When the measurement is com-
plete, the MEAS icon will cease
flashing and the displayed value will
be locked.
5. Press the MEAS button again to unlock the LCD and
return to dynamic reading mode. After rinsing the sensor,
steps 1 - 4 can then be repeated.
Measurements can be made without pressing the MEAS
button. In this case, the meter will remain in dynamic
measurement mode.

13
Submerged Measurement
1. Open the light shield cover’s sliding cap. Submerge
the senor in the sample and shake it gently 2 or 3 times
2. When the stability icon appears, proceed as with flat
surface measurements (p. 12).
Scoop Measurement
1. Open the light shield cover’s sliding cap. Submerge
the sensor in the sample and shake it gently 2 or 3 times.
Scoop up some of the sample onto the meter. Place the
meter on a flat surface.
2. When the stability icon appears, proceed as with flat
surface measurements (p. 12).
Temperature Measurement
The meter has an internal temperature sensor. A reading
can be taken in special settings mode 2 (see p. 15).

14
Setting Special Modes
The Cardy nitrate meter has 6 special modes that can be
modified at the user’s discretion. The modes are:
1. Set measurement units
2. Temperature measurement
3. Set number of calibrations
4. Set slope coefficient
5. Set offset coefficient
6. Voltage measurement
Entering Special Setting Mode
Press and hold the MEAS button
for, at least, 5 seconds while the
meter is in measurement mode.
Release the MEAS button as soon
as you see all the LCD elements
illuminated.
The LCD will then transition to
special setting mode starting with
the screen for mode 1. If the MEAS
button is not released immediately
after seeing the full display, the me-
ter will enter the “Set measurement
units” mode and display the word
“Unit”. In this case, press and hold the MEAS button to
return to measurement mode and start over.
To scroll to the next mode, press the CAL button for half
a second. If the CAL button is held down, the meter will
cycle through the modes sequentially.
Once in the desired mode selection screen, press and hold
the MEAS button for half a second to modify that con-
figuration. Pressing and holding the MEAS button will
take you out of special setting mode. See the following
pages for details on each mode.
Full display screen
Sample mode
selection screen

15
Mode 1 (Set measurement units)
From mode selection screen 1, press the MEAS button for
half a second. From here, you can configure which units
will be displayed. Press the CAL button for half a second
to cycle to the desired option. The choices are:
ppm NO3-- N, ppm NO3-, mg/L NO3-- N, and mg/L NO3-
Press and hold the MEAS button to return to measure-
ment mode.
Mode 2 (Temperature measurement)
From mode selection screen 2, press the MEAS button for
half a second. This is not a mode configuration screen.
Instead, in this mode, the meter displays the reading of the
internal temperature sensor (in Celsius). The measurement
precision is not guaranteed and should only used as an es-
timate.
Press and hold the MEAS button to return to measure-
ment mode.
MEAS button
MEAS button

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Mode 3 (Set number of calibrations)
From mode selection screen 3, press the MEAS button for
half a second. From here, you can configure the number
of solutions that will be used to calibrate the meter. The
options are 1- and 2-point calibration. Press the CAL but-
ton for half a second to cycle to the desired option.
Press and hold the MEAS button to return to measure-
ment mode.
Mode 4 (Set slope coefficient)
From mode selection screen 4, press the MEAS button for
half a second. From here, you can set a multiplicative
constant (0.1 to 9.9) that will be multiplied by the reading.
This, along with the offset setting (mode 5), can be used
to modify the output value to suit a specific application
such as dilute or concentrated solutions. The default set-
ting is 1.00.
Press and hold the MEAS button to return to measure-
ment mode.
MEAS button
MEAS but-

17
Mode 5 (Set offset coefficient)
From mode selection screen 5, press the MEAS button for
half a second. From here, you can set an additive constant
(-1000 to 1000) that will be added to the reading. This,
along with the slope setting (mode 4), can be used to mod-
ify the output value to suit a specific application such as
dilute or concentrated solutions. The default setting is 0.
Press and hold the MEAS button to return to measure-
ment mode.
Mode 6 (Sensor voltage measurement)
From mode selection screen 6, press the MEAS button for
half a second. This is not a mode configuration screen.
Instead, in this mode, the meter displays the reading of the
sensor voltage (in mV). Use this mode to evaluate sensor
performance or to create your own calibration curve.
Press and hold the MEAS button to return to measure-
ment mode.
MEAS button
MEAS button

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Replacing the Sensor
Removal
Lift hole aoff tab Aand slide the sensor away from the
chassis.
Replacement
Slide the sensor onto the body so that tab Afits into hole
a. Take care not to twist the waterproof gasket
Precautions
• As shown here, make sure that
the sensor tab is inserted over
the copper strip on the main
unit. Be careful not to dam-
age the connector
• When removing the sensor, carefully wipe off any
drops of sample remaining on the water proof gasket.
Do not let water permeate the main body.
• When replacing the sensor or batteries, be sure the unit
is powered off.

19
Installing and
Replacing Batteries
Installation
Slide both batteries into the bat-
tery clips as shown such that the
positive sides are facing up-
ward.
Replacement
Use a small flat-head screwdriver
or other instrument to pry the bat-
teries from the clips as shown.
Always replace both batteries at
once.

20
Sample Collection
Collect at least 15 to 20 core samples from an area not ex-
ceeding ten acres by using a Z pattern. Areas having dif-
ferent soil types or management histories should be sam-
pled separately. Sample the top 12 inches of soil. Some
universities recommend sampling the top 24 inches in 12
inch increments. Contact your county extension agent for
recommendations. Care should be taken to ensure that
soil samples are not biased by the presence of rows or
bands of fertilizer.
Soil Preparation
Samples should be dried within 24 hours of collection to
minimize changes in NO3--N concentrations. Before dry-
ing, crumble the soil to avoid large clods that will be diffi-
cult to crush when dry. The samples should then be dried
by spreading on a thin layer of newspaper at least 3 pages
thick and placing overnight in a warm spot with good air
movement. Soil will dry in a few hours if placed in a
sunny location exposed to the wind. If dried indoors, 24
to 48 hours may be required. Indoor drying time can be
reduced with the use of a fan. For oven drying, spread a
thin layer of soil on a cookie sheet or pie plate. Place it in
an oven set to no more than 250oF with the door slightly
ajar. Consider the soil dry when it crumbles rather than
compacts under pressure. After drying, crush the soil by
using a block of wood or other suitable device. Crush un-
til the soil particles are the size of BB’s or smaller. Sift
with a flour sifter or other 10 mesh screen. Mix soil thor-
oughly.
Soil testing of mineral soil requires the Soil Test Kit (item
#2330). Be sure you are using the soil standard solutions
(item nos. 2334L and 2336) when calibrating the meter for
soil tests. Do not use the calibration standards for water/
plant sap (See Calibrating Solutions, p. 8).
Preparing Soil Samples