Hanna Instruments hi 93705 User Manual

MEASUREMENT PROCEDURE

• Turn the meter on by pressing ON/OFF.

• When the LCD displays “- - -”, it is

ready.

• Fill the cuvet with 10 mL of

unreacted sample up to the
mark.

• Add 6 drops of HI 93705A

molybdate reagent. Re-
place the cap and swirl
the solution.

• Wait for 4 minutes, add

the content of one packet
of HI 93705B citric acid
reagent and shake until it
is completely dissolved.

• Wait for 1 minute. This is the blank.

• Place the cuvet into the holder

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

• Press ZERO and “SIP” will appear on the display.

• Wait for a few seconds and the display

will show “-0.0-”. Now the meter is
zeroed and ready for measurement.

ON

OFF

12

3

6

9

1’

ZERO

READ

TIMED

12

3

6

9

1’

READ

DIRECT

• Remove the cuvet and add

the content of one packet of
HI 93705C amino acid re-
agent and shake until it has
dissolved.

• Reinsert the cuvet into the in-

strument.

• Press READ TIMED and the display will show the count-

down prior to the measurement. Alternatively, wait for
exactly 1 minute and press READ DIRECT. In both cases
“SIP” will appear during measurement.

• The instrument directly displays concentration in mg/L of

silica (SiO

2

) on the Liquid Crystal Display.

INTERFERENCES

Interference may be caused by:
Phosphate above 60 mg/L (causes a 2% reduction in
reading)
Phosphate above 75 mg/L (causes an 11% reduction in
reading)
Sulfide and high concentration of iron
Eliminate color and turbidity interferences by zeroing the
meter with the original water sample.

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 it

is recommended that a zero reading be taken for each
sample and 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.

• All the reaction times reported in this manual are

referred to 20°C (68°F). As a general rule of thumb,
they should be doubled at 10°C (50°F) and halved at
30°C (86°F).

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 attach a fresh
9V battery while paying attention to the correct polarity.
Replace the battery and the cover.

9V

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.

REAGENT SETS

HI 93705-01 Reagents for 100 tests
HI 93705-03 Reagents for 300 tests

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).

IST93705R2

10/99

PRINTED IN PORTUGAL