Hanna Instruments HI 93735 User Manual

Page 2

OPERATIONAL GUIDE

MEASUREMENT PROCEDURE

• Turn the meter on by pressing ON/OFF.

• When the LCD displays "SCL",

it is ready.

• The meter automatically defaults to Hardness Low Range

(LR) measurement mode, with the “HARDNESS” and
“LR” indications appearing on the LCD. Press the “RANGE”
key to select the Medium Range (MR) or the High
Range (HR) if needed. If the “RANGE” key is pressed
while in HR mode, the meter returns to LR range.

• Using the syringe, add exactly 0.5mL of

unreacted sample to the cuvet.

Note: for accurate results, fill the syringe with

the sample up to the 1.0mL mark,
then transfer 0.5mL to the cuvet.

• With the plastic dropper fill the cuvet up

to the 10 mL mark adding the HI93735A
indicator reagent appropriate to the se-
lected range (e.g. HI93735A-LR if the
range selected is LR).

Note: the liquid in the cuvet forms a convexity

on the top; the bottom of this convexity
must be at the same level of the 10mL mark.

• Add 2 drops of HI93735B buffer re-

agent.

• Replace the cap and shake gently to

mix.

• Place the cuvet into the holder and

ensure that the notch on the cap is
positioned securely into the groove.

OFF

• Press “ZERO/READ”. The display will show a countdown

prior to measurement. During measurement the “bLn”
indication will be shown, then “-0-” will appear.

• Remove the cuvet and add the content of 1

packet of HI93735C fixing reagent.

• Replace the cap and shake gently to

mix.

• Reinsert the cuvet into the holder

and ensure that the notch on the
cap is positioned securely into the
groove.

• Press “ZERO/READ”. The display will show a countdown

prior to measurement. During measurement the “SIP”
indication will be displayed.

• The instrument directly displays the hardness in ppm of

CaCO

on the Liquid Crystal Display.

• Press the “UNIT” key repeatedly to have

the reading converted in °f, °D and °E
respectively.

The conversion factors are as follows:

1 ppm = 0.1 °f = 0.05556 °D = 0.07 °E

• Press the “RANGE” key to have the meter ready for the

next measurement.

INTERFERENCES

Interference may be caused by:
Excessive amounts of heavy metals
Note: if the sample is very acidic, some extra drops of

HI93735B buffer reagent may be added.

The instruction listed below should be carefully followed
during testing to ensure best accuracy.
• Do not touch the cuvet walls with hands.
• 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.

• Do not let the test sample stand too long after reagent

is added or accuracy will be lost.

• Whenever the cuvet is placed into the measurement cell,

it must be completely free of fingerprints, oil or dirt.
Wipe it thoroughly with HI 731318 or a lint-free cloth
prior to insertion.

• It is important that the sample does not contain any

debris. This would corrupt the readings.

• It is possible to take multiple readings in a row, but a

zero reading must be taken for each sample and it is
recommended that the same cuvet is used for zeroing
and measurement.

• It is important to discard the sample immediately after

the reading is taken because the glass might become
permanently stained.

• Shaking the cuvet can generate bubbles in the sample,

causing higher readings. To obtain accurate measure-
ments, remove such bubbles by swirling or by gently
tapping the vial.

TIPS FOR AN ACCURATE

MEASUREMENT

BATTERY REPLACEMENT

Battery replacement must only take place in a non-hazard-
ous area using a 9V alkaline battery.
Simply slide off the battery cover on
the back of the meter. Detach the
battery from the terminals and at-
tach a fresh 9V battery while paying
attention to the correct polarity. Re-
place the battery and the cover.

SLIDE

OFF

ACCESSORIES

REAGENT SETS

HI 93735LR Reagents for 100 tests LR (0 to 250 ppm)
HI 93735MR Reagents for 100 tests MR (200 to 500 ppm)
HI 93735HR Reagents for 100 tests HR (400 to 750 ppm)
HI 93735-0 Reagents for 100 tests (0 to 750 ppm)

OTHER ACCESSORIES

HI 710009 Blue rubber boot
HI 710010 Orange rubber boot
HI 721310 9V battery (10 pcs)
HI 731318 Tissue for wiping cuvets (4 pcs)
HI 731321 Glass cuvets (4 pcs)
HI 731325 Caps for cuvets (4 pcs)
HI 93703-50 Cuvets cleaning solution (230 mL).

CE DECLARATION

OF CONFORMITY

IST93735R1

03/99

PRINTED IN PORTUGAL

Recommendations for Users
Before using these products, make sure that they are entirely suitable for the environ-
ment in which they are used. Operation of these instruments in residential area could
cause unacceptable interferences to radio and TV equipments, requiring the operator to
take all necessary steps to correct interferences. Any variation introduced by the user to
the supplied equipment may degrade the instruments' EMC performance.
To avoid damages or burns, do not perform any measurement in microwave ovens.