HI 95725C
Instruction Manual
HI 95725C
Free & Total Chlorine
Cyanuric Acid / pH
ISM
www.hannainst.com
This Instrument is in
Compliance with the CE Directives
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Dear Customer,
Thank you for choosing a Hanna product. This manual will provide you with the necessary
information for the correct use of the instrument. Please read it carefully before using the meter.
If you need additional technical information, do not hesitate to e-mail us at tech@hannainst.com.
This instrument is in compliance with directives.
TABLE OF CONTENTS
PRELIMINARY EXAMINATION ..............................................................................................3
GENERAL DESCRIPTION ......................................................................................................4
ABBREVIATIONS ................................................................................................................4
SPECIFICATIONS ................................................................................................................ 5
PRECISION AND ACCURACY................................................................................................. 5
PRINCIPLE OF OPERATION .................................................................................................. 6
FUNCTIONAL DESCRIPTION .................................................................................................7
GUIDE TO DISPLAY CODES .................................................................................................. 9
GENERAL TIPS FOR AN ACCURATE MEASUREMENT ...........................................................11
OPERATIONAL GUIDE .......................................................................................................12
CHLORINE (FREE & TOTAL) ............................................................................................. 13
CYANURIC ACID ...............................................................................................................16
PH ..................................................................................................................................18
VALIDATION PROCEDURE .................................................................................................20
CALIBRATION PROCEDURE ............................................................................................... 21
BATTERY REPLACEMENT ..................................................................................................24
ACCESSORIES .................................................................................................................24
WARRANTY .................................................................................................................25
CE DECLARATION OF CONFORMITY ................................................................................... 26
HANNA LITERATURE ........................................................................................................27
PRELIMINARY EXAMINATION
Please examine this product carefully. Make sure that the instrument is not damaged. If any
damage occured during shipment, please notify your Dealer.
Each HI 95725C Ion Selective Meter is supplied complete with:
• Two Sample Cuvets and Caps
• 9V Battery
• Scissors
• Tissue for wiping cuvets
• Two CAL CHECK™ cuvets (HI 95725-11) with Quality Certificate
• Instruction Manual
• Instrument Quality Certificate and Quick Reference Guide
• 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.
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.
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GENERAL DESCRIPTION
SPECIFICATIONS
The HI 95725 is an auto diagnostic portable microprocessor meter that benefits from Hanna’s
years of experience as a manufacturer of analytical instruments. It has the 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 CHECK™ 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 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 codes 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 or after 1 hour if left in the
The meter uses an exclusive positive-locking system to ensure that the cuvet is in the same
position every time it is placed into the measurement cell. It is designed to fit a cuvet with a
larger neck making it easier to add both sample and reagents. The cuvet is made from special
optical glass to obtain best results.
The HI 95725 meter measures the free and total chlorine (Cl2), the cyanuric acid and the pH in
water samples.
The liquid reagents are supplied in dropper bottles and the powder reagent in easy to handle
powder packets. The amount of reagent is precisely dosed to ensure the maximum repeatability.
calibration mode
.
ABBREVIATIONS
°C: degree Celsius
USEPA: US Environmental Protection Agency
°F: degree Fahrenheit
mg/L: milligrams per liter. mg/L is equivalent to ppm (part per million)
mL: milliliter
Light Source Tungsten lamp with narrow band interference filter @ 525 nm.
Light Detector Silicon Photocell
Environment 0 to 50°C (32 to 122°F); max 95% RH non-condensing
Battery Type 1 x 9 volt
Auto-Shut off After 10' of non-use in
after 1 hour of non-use in
Dimensions 180 x 83 x 46 mm (7.1 x 3.3 x 1.8")
Weight 290 g (10 oz.)
For specifications related to each single parameter (e.g. range, accuracy, etc.), refer to the
related measurement section.
measurement mode
calibration mode
;
.
PRECISION AND ACCURACY
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
reagents, an operator obtained with a single
instrument a standard deviation of 0.03 mg/L.
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PRINCIPLE OF OPERATION
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 = ελ c d
or
A = ελ c d
Where:
-log I/I
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's HI 95000 series colorimeters is based on special subminiature
tungsten lamps and narrow-band interference filters to guarantee both high performance and
reliable results.
= Absorbance (A)
o
Io= intensity of incident light beam
I = intensity of light beam after absorption
ελ= molar extinction coefficient at wavelength λ
c = molar concentration of the substance
d = optical path through the substance
A microprocessor controlled special tungsten lamp emits radiation which is first optically
conditioned and beamed to the sample contained in the cuvet. The optical path is fixed by the
diameter of the cuvet. Then the light is spectrally filtered to a narrow spectral bandwidth, to
obtain a light beam of intensity Io or I.
The photoelectric cell collects the radiation I that 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 cuvet 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) cuvets are
optically identical to provide the same measurement conditions. Whenever possible use the same
cuvet for both. It is necessary that the surface of the cuvet 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 cuvet walls with hands.
Furthermore, in order to maintain the same conditions during the zeroing and the measuring
phases, it is necessary to close the cuvet to prevent any contamination.
FUNCTIONAL DESCRIPTION
1) Liquid Crystal Display
2) Cuvet Holder
3) Cuvet alignment indicator
4) ON/OFF key
5) ZERO/SET key
6) READ key
7) CAL CHECK key
Block diagram (optical layout)
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KEYPAD DESCRIPTION
• ON/OFF: to turn the meter on and off.
• ZERO: press to zero the meter prior to measurement.
• READ: press for making a measurement.
• CAL CHECK: this bi-functional key allows to perform validation of the instrument just pressing
the CAL CHECK key, or hold the key for 3 seconds to enter the
calibration mode
.
OPERATING MODES
•
Measurement mode:
•
Calibration mode:
default operation mode, enables both validation and measurement.
may be entered by keeping CAL CHECK pressed for three seconds (the “CAL”
icon appears), it enables calibration of the instrument.
GUIDE TO DISPLAY CODES
This prompt appears for 1 second each time the instrument is turned on.
The parameter code “Cl”, “CYS” or “PH” indicates that the meter is in
a ready state and zeroing can be performed. The parameter code that
appears is the one of the last selected parameter (Cl=free and total
chlorine, CYS=cyanuric acid or PH=pH).
Sampling in Progress. This flashing prompt appears each time the meter
is performing a measurement.
This indicates that the meter is in a zeroed state and measurement can
be performed.
DISPLAY ELEMENTS DESCRIPTION
1) four digit main display area.
2) CAL: appears when the instrument operates in the
calibration mode.
3) the Month and Day icons appear above the number of month and day when a date is
displayed.
4) the blinking “Battery” icon appears when the battery voltage is getting low.
The blinking "BAT" indicates that the battery voltage is getting low and
the battery needs to be replaced.
This indicates that the battery is dead and must be replaced. Once this
indication is displayed, the meter will lock up. Change the battery and
restart.
“Configuration”: this indicates that the meter has lost its configuration.
Contact your dealer or the nearest Hanna Customer Service Center.
CALIBRATION MODE MESSAGES (only for chlorine)
The date of the last calibration appears on the LCD each time the
calibration mode
is entered. If calibration is performed for the first time,
“F.CAL” appears.
This indicates that the factory calibration is selected.
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The flashing digits indicate that:
1) the month can be set
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2) the day can be set
“Storage”: this prompt appears for 1 second at the end of the calibration procedure, to indicate that the calibration data has been stored.
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