Hanna Instruments HI96725C User manual

1
INSTRUCTION MANUAL
HI96725C
Chlorine, Cyanuric Acid & pH ISM

Thank you for choosing a Hanna Instruments product.
Please read this instruction manual carefully before using the instrument.
This manual will provide you with the necessary information for correct use of
the instrument, as well as a precise idea of its versatility.
If you need additional technical information, do not hesitate to e‑mail us at
[email protected] or view our worldwide contact list at www.hannainst.com.
All rights are reserved. Reproduction in whole or in part is prohibited without the written consent
of the copyright owner, Hanna Instruments Inc., Woonsocket, Rhode Island, 02895, USA.
Dear
Customer,

3
PRELIMINARY EXAMINATION ............................................................................................
GENERAL DESCRIPTION ....................................................................................................
ABBREVIATIONS ..............................................................................................................
SPECIFICATIONS ..............................................................................................................
PRECISION AND ACCURACY ..............................................................................................
PRINCIPLE OF OPERATION ...............................................................................................
FUNCTIONAL DESCRIPTION ...............................................................................................
ERRORS AND WARNINGS .................................................................................................
GENERAL TIPS FOR AN ACCURATE MEASUREMENT .............................................................
STARTUP ........................................................................................................................
RANGE SELECTION............................................................................................................
MEASUREMENT PROCEDURE ............................................................................................
VALIDATION PROCEDURE .................................................................................................
CALIBRATION PROCEDURE ...............................................................................................
GLP ................................................................................................................................
BATTERY MANAGEMENT ...................................................................................................
BATTERY REPLACEMENT ...................................................................................................
ACCESSORIES ..................................................................................................................
4
5
6
7
11
14
16
21
25
5
7
9
13
15
19
24
26
TABLE OF CONTENTS
26

4
heckTM
Please examine this product carefully. Make sure that the instrument is not damaged. If any damage
occurred during shipment, please contact your local Hanna Instruments Office.
Each HI96725 Ion Selective Meter is supplied complete with:
• Sample Cuvettes and Caps (2 pcs.)
• CAL CheckTM Standard Cuvettes (5 pcs.)
• 9V Battery
• Scissors
• Cloth for wiping cuvettes
• Instruction Manual and Quick Reference Guide
• Quality Certificate
• Rigid carrying case
Note: Save all packing material until you are sure that the instrument works correctly. Any
defective item must be returned in its original packing.
PRELIMINARY EXAMINATION

5
The HI96725 is an auto diagnostic portable microprocessor meter that benefits from Hanna
Instruments’ years of experience as a manufacturer of analytical instruments. It has an advanced
optical system based on a special tungsten lamp and a narrow band interference filter that allows
most accurate and repeatable readings. All instruments are factory calibrated and the electronic
and optical design minimizes the need of frequent calibration.
With the powerful CAL CheckTM validation function, you are able to validate good performance
of your instrument at any time. The validation procedure is extremely user friendly. Just use the
exclusive Hanna Instruments ready‑made, NIST traceable standards to verify the performance of
the instrument and recalibrate if necessary.
All instruments are splash proof and the lamp and filter units are protected from dust or dirt by
a transparent cup. This makes the instruments fulfill field applications. Display messages aid the
user in routine operation. The meter has an auto‑shut off feature that will turn off the instrument
after 10 minutes of non use in measurement mode or after 1 hour if left in calibration mode.
The meter uses an exclusive positive‑locking system to ensure that the cuvette is in the same
position every time it is placed into the measurement cell. It is designed to fit a cuvette with a
larger neck making it easier to add both sample and reagents. The cuvette is made from special
optical glass to obtain best results.
The HI96725 meter measures the pH value in the 6.5 to 8.5 range, the free and total chlorine
(Cl2) in water samples in the 0.00 to 5.00 mg/L (ppm) range, and cyanuric acid in the 0 to
80 mg/L range. The methods are phenol red for pH, an adaptation of the USEPA Method 330.5
for wastewater, and Standard Method 4500‑Cl G for drinking water for free and total chlorine and
an adaptation of the turbidimetric method for cyanuric acid.
The reagents are in powder and liquid form and supplied in packets or bottles. The amount of
reagent is precisely dosed to ensure the maximum repeatability.
degree Celsius
US Environmental Protection Agency
degree Fahrenheit
milligrams per liter. mg/L is equivalent to ppm (parts per million)
milliliter
millivolt
°C:
USEPA:
°F:
mg/L:
mL:
mV:
GENERAL DESCRIPTION ABBREVIATIONS

6
Range
Free Cl2 0.00 to 5.00 mg/L
Total Cl2 0.00 to 5.00 mg/L
Cyanuric Acid 0 to 80 mg/L
pH 6.5 to 8.5
Resolution
0.01 mg/L under 3.50 mg/L Chlorine
0.10 mg/L above 3.50 mg/L Chlorine
1 mg/L Cyanuric Acid
0.1 pH
Accuracy
@25 °C (77 °F)
Free Cl2 ±0.03 mg/L ±3% of reading
Total Cl2 ±0.03 mg/L ±3% of reading
Cyanuric Acid ±1 mg/L±15% of reading
pH ±0.1 pH
Light source Tungsten lamp
Light Detector Silicon Photocell @525 nm filter
Method
For Cl2: Adaptation of the USEPA method and Standard Method 4500‑Cl G. The re‑
action with reagents causes a pink tint in the sample.For Cyanuric Acid: Adaptation
of the turbidimetric method. The reaction between cyanuric acid and the reagent
causes a white suspension in the sample. For pH: Phenol red method. The reaction
with reagents causes a red tint in the sample.
Environment 0 to 50 °C (32 to 122 °F); max 95% RH non‑condensing
Battery Type 9V (1 pc.)
Auto‑Shut off After 10’ of non‑use in measurement mode; after 1 hour of non‑use in calibration
mode; with last reading reminder
Dimensions 192 x 104 x 69 mm (7.6 x 4.1 x 2.7”)
Weight 320 g (11.3 oz.)
Required Reagents
Code Unit Description Quantity/Test
HI93701-0 Free Cl2 DPD Powder Reagent 1 packet
HI93711-0 Total Cl2 DPD Powder Reagent 1 packet
HI93722-0 Cyanuric Acid 1 packet
HI93710-0 pH 5 drops
SPECIFICATIONS

7
Absorption of Light is a typical phenomenon of interaction between electromagnetic radiation and
matter. When a light beam crosses a substance, some of the radiation may be absorbed by atoms,
molecules or crystal lattices.
If pure absorption occurs, the fraction of light absorbed depends both on the optical path length
through the matter and on the physical‑chemical characteristics of the substance according to the
Lambert‑Beer Law:
‑log I/Io= ελc d
or
A = ελc d
Where:
‑log I/Io = Absorbance (A)
Io = intensity of incident light beam
I = intensity of light beam after absorption
ε
λ= molar extinction coefficient at wavelength λ
c = molar concentration of the substance
d = optical path through the substance
Precision is how closely repeated measurements
agree with each other. Precision is usually
expressed as standard deviation (SD).
Accuracy is defined as the nearness of a test result
to the true value.
Although good precision suggests good accuracy,
precise results can be inaccurate. The figure
explains these definitions. In a laboratory using
a standard solution of 1.00 mg/L chlorine and a
representative lot of reagent, an operator obtained
with a single instrument a standard deviation of
0.02 mg/L.
PRECISION AND ACCURACY PRINCIPLE OF OPERATION

8
A microprocessor controlled special tungsten lamp emits radiation which is first optically conditioned
and beamed to the sample contained in the cuvette. The optical path is fixed by the diameter of
the cuvette. Then the light is spectrally filtered to a narrow spectral bandwidth, to obtain a light
beam of intensity Ioor I.
The photoelectric cell collects the radiation Ithat is not absorbed by the sample and converts it
into an electric current, producing a potential in the mV range.
The microprocessor uses this potential to convert the incoming value into the desired measuring
unit and to display it on the LCD.
The measurement process is carried out in two phases: first the meter is zeroed and then the actual
measurement is performed.
The cuvette has a very important role because it is an optical element and thus requires particular
attention. It is important that both, the measurement and the calibration (zeroing) cuvettes, are
optically identical to provide the same measurement conditions. Whenever possible use the same
cuvette for both. It is necessary that the surface of the cuvette is clean and not scratched. This to avoid
measurement interference due to unwanted reflection and absorption of light. It is recommended
not to touch the cuvette walls with hands.
Furthermore, in order to maintain the same conditions during the zeroing and the measuring phases,
it is necessary to close the cuvette to prevent any contamination.
Therefore, the concentration “c” can be calculated from the absorbance of the substance as the
other factors are known.
Photometric chemical analysis is based on the possibility to develop an absorbing compound from a
specific chemical reaction between sample and reagents. Given that the absorption of a compound
strictly depends on the wavelength of the incident light beam, a narrow spectral bandwidth should
be selected as well as a proper central wavelength to optimize measurements.
The optical system of Hanna Instruments’ HI96 series colorimeters is based on special subminiature
tungsten lamps and narrow‑band interference filters to guarantee both high performance and
reliable results.
HI96 series block diagram (optical layout)
PRINCIPLE OF OPERATION

9
1) RANGE/GLP key
2) CAL CHECK key
3) ZERO/CFM key
4) READ /TIMER key
5) ON/OFF key
6) Liquid Crystal Display (LCD)
7) Cuvette alignment indicator
8) Cuvette holder
INSTRUMENT DESCRIPTION
KEYPAD DESCRIPTION
• ON/OFF: to turn the meter on and off.
• ZERO/CFM: this is a bi‑functional key. Just press to zero the meter prior to measurement, or
confirm edited values. In calibration mode press to confirm factory calibration restore.
• READ /TIMER: this is a multi‑functional key. In measurement mode, press to make a
measurement, or press and hold for three seconds to start a pre‑programmed countdown prior
to measurement. In GLP mode press to view the next screen.
• CAL CHECK: this is a bi‑functional key. Just press to perform the validation of the meter, or
press and hold for three seconds to enter calibration mode.
• RANGE/GLP : this is a multi‑functional key. Just press to change the parameter. Press and
hold for three seconds to enter GLP mode. In calibration mode press to edit the date and time.
FUNCTIONAL DESCRIPTION

10
DISPLAY ELEMENTS DESCRIPTION
1) The measuring scheme (lamp, cuvette, detector), appears during different phases of zero or
reading measurement
2) Error messages and warnings
3) The battery icon indicates the charge state of the battery
4) The hourglass appears when an internal check is in progress
5) Status messages
6) The chronometer appears when the reaction timer is running
7) The month, day and date icons appear when a date is displayed
8) Four digit main display
9) Measuring units
10) Four digit secondary display
OPERATING MODES
• Measurement mode:default operation mode, enables both validation and measurement.
• Calibration mode:may be entered by keeping CAL CHECK pressed for three seconds (the
“CAL” tag appears), it enables calibration of the instrument.
• GLP mode:may be entered by keeping RANGE/GLP pressed for three seconds (“GLP”
appears), it enables consulting of user calibration date or restore factory calibration.
FUNCTIONAL DESCRIPTION