Eclox Manual

Section 7 Free and Total Chlorine Test

7.1 Measuring hints and general information

• Clean all labware between tests. Contamination may change test results. Clean labware with a non-abrasive detergent or a solvent, such as isopropyl alcohol.

Use a soft cloth for cleaning or drying. Do not use paper towels or tissue on plastic tubes as scratches may occur. Remove detergent or solvent with clean water (preferably demineralized water).

• Clean all viewing tubes thoroughly with the sample water before testing.

• To open PermaChem

®

powder pillows:

1. Tap the bottom of the pillow on a hard surface.

2. Open the pillow along the dashed line.

3. Open the pillow and pinch the side edges to make a spout.

4. Put the contents in the sample.

• Accuracy is not affected by undissolved powder.

• The manufacturer strongly recommends that, for optimum results, the user make sure the reagent is accurate for each new lot of reagents. Use the standard solution included in this kit or listed in

Replacement parts and accessories on page 117 . Do the instructions included with each standard

solution.

7.2 Free chlorine procedure, 0–3.5 mg/L

1. Fill a viewing tube to the first (5 mL) line with sample water. This is the blank.

2. Put the tube in the top-left opening of the color comparator.

3. Fill another viewing tube to the first (5-mL) line with sample water.

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4. Add the contents of one

DPD free chlorine reagent powder pillow to the second tube.

Complete the test and read the result within one minute of adding the powder.

5. Swirl to mix.

6. Put the second tube in the top-right opening of the color comparator.

7. Hold the comparator up to a light source and look through the openings in the front.

8. Turn the color disc until the color matches in the two openings.

9. Read the mg/L free chlorine in the scale window.

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7.3 Total chlorine procedure, 0–3.5 mg/L

1. Fill a viewing tube to the first (5-mL) line with sample water. This is the blank.

2. Put the tube in the top-left opening of the color comparator.

3. Fill another viewing tube to the first (5-mL) line with sample water.

4. Add the contents of one

DPD total chlorine reagent powder pillow to the second tube.

5. Swirl to mix. Wait three minutes.

The result of the test must be read within six minutes of adding the powder.

6. Put the second tube in the top-right opening of the color comparator.

7. Hold the comparator up to a light source and look through the openings in the front.

8. Turn the color disc until the color matches in the two openings.

9. Read the mg/L total chlorine in the scale window.

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