User Guide

ManualsBrandsHanna Instruments ManualsOtherHI 933000

The TDS value in aqueous solutions is directly proportional to conduc-

tivity. The ratio between the two parameters depends on the solution

and usually it is set to a factor of 0.5 (corresponding to a solution of

CaCO

). This means that 1 µS/cm is equal to 0.5 mg/L (ppm) of TDS.

For manual temperature compensation, refer to the following chart:

TDS VERSUSTDS VERSUS

TDS VERSUS

TEMPERATURE CHARTTEMPERATURE CHART

TEMPERATURE CHART

For instance, the TDS values of the calibration solutions at 25°C are

1382 mg/L or 12.41 g/L when using HI 7032 or HI 7036, respec-

tively.

At 20°C, the values are 1251 mg/L or 11.24 g/L, respectively.

With the solutions at 30°C, the values are 1515 mg/L or 13.61 g/L,

respectively.

°C °F HI 7032 HI 7036

mg/L g/L

(ppm) (ppt)

0 32 758 6.82

5 41 876 7.88

10 50 999 8.99

15 59 1122 10.10

16 60.8 1148 10.33

17 62.6 1173 10.56

18 64.4 1200 10.78

19 66.2 1224 11.01

20 68 1251 11.24

21 69.8 1277 11.47

22 71.6 1303 11.71

23 73.4 1329 11.94

24 75.2 1358 12.18

2525

7777

13821382

1382

12.4112.41

12.41

26 78.8 1408 12.65

27 80.6 1438 12.89

28 82.4 1461 13.13

29 84.2 1476 13.37

30 86 1515 13.61

31 87.8 1541 13.85

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Highly acidic, alkaline samples or solutions with high salt content

might have a different coefficient than the customary 2% per degree °C.

In order to calculate this coefficient follow the procedure below:

• Immerse the probe of HI 8733 in the sample and adjust the

TEMPERATURE COEFFICIENT knob to 0% (i.e. no compensation).

• Condition the sample and probe to 25°C and note the conductiv-

ity reading, C

• Condition the sample and probe to a different temperature t°C

(approximately 10°C different from 25°C) and note the conduc-

tivity reading C

• The temperature coefficient ß of the solution is calculated as given

by the following formula:

- C

)

ß = 100 x

(t - 25) x C

The above procedure is suitable for determining the temperature

coefficient in a laboratory or where the temperature of the solution

can be controlled.

If this is not possible (e.g. on-site measurements), the following

procedure can be used providing the sample temperature varies by at

least 5°C or preferably 10°C:

• Immerse the probe of HI 8733 in the test solution and turn the

TEMPERATURE COEFFICIENT knob to 0% (no compensation).

• Check the conductivity reading and record the value. Make sure

the reading is stable, i.e. no greater variations than ±0.2 mS/

cm within a minute.

• Repeat the procedure when the temperature of the test solution

has changed by at least 5°C. Wait for the conductivity reading to

stabilize.

• Adjust the TEMPERATURE COEFFICIENT knob until the display

shows the same value as recorded earlier.

• The value indicated by the knob is the temperature coefficient of

the solution.

2.5

1.51

0.5

TEMPERATURE COEFFICIENT

DETERMINING THE TEMPERATUREDETERMINING THE TEMPERATURE

DETERMINING THE TEMPERATURE

COEFFICIENT OF A SOLUTION (HI 8733)COEFFICIENT OF A SOLUTION (HI 8733)

COEFFICIENT OF A SOLUTION (HI 8733)