Water Quality Monitoring

This test is made by comparing the turbidity of a measured amount of the sample with an identical amount of turbidity-free water containing a measured amount of standardized turbidity reagent. The readings are made by looking down through the column of liquid at a black dot. If turbidity is present, it will interfere with the passage of light through the column of liquird. Small amounts of turbidity will cause a "blurring" of the black dot in the bottom of the tube. Large amounts of turbidity may provide sufficient "cloudiness" so that it is not possible to see the black dot when looking down through the column. Any color that may be present in the sample should be disregarded. This determination is concerned only with the haziness or cloudy nature of the sample.

1. Fill one Turbidity Column (0835) to the 50 ml. line with the sample water. If the black dot on the bottom of the tube is not visible when looking down through the column of liquid, pour out a sufficient amount of the test sample so that the tube is filled to the 25 ml. line.
   
   
2. Fill the second Turbidity Column (0835) with an amount of turbidity-free water that is equal to the amount of sample being measured. Distilled water is preferred; however, clear tap water may be used. This is the "clear water" tube.
   
   
3. Place the two tubes side by side and note the difference in clarity. If the black dot is equally clear in both tubes, the turbidity is zero. If the black dot in the sample tube is less clear, proceed to Step 4.
   
   
4. Shake the Standard Turbidity Reagent (7520) vigorously. Add 0.5 ml. to the "clear water" tube. Use the sitting rod (1114) to stir the contents of both tubes to equally distribute the turbid particles. Check for the amount of turbidity by looking down through the solution at the black dot. If the turbidity of the sample water is greater than that of the "clear water", continue to add Standard Turbidity Reagent in 0.5 ml. increments to the "clear water" tube, mixing after each addition until the turbidity equals that of the sample. Record total amount of Turbidity Reagent added.
   
   
5. Each 0.5 ml. addition to the 50 ml. size sample is equal to 5 Jackson Turbidity Units (JTU's). If a 25 ml. sample size is used, each 0.5 ml. addition of the Standard Turbidty Reagent is equal to 10 JTU's. (See the table below.) Rinse both tubes carefully after each determination.

Turbidity Test Results

Number of Measured Additions	Amount in ml.	50 ml. Sample	25 ml. Sample
1	0.5	5 JTU	10 JTU
2	1.0	10 JTU	20 JTU
3	1.5	15 JTU	30 JTU
4	2.0	20 JTU	40 JTU
5	2.5	25 JTU	50 JTU
6	3.0	30 JTU	60 JTU
7	3.5	35 JTU	70 JTU
8	4.0	40 JTU	80 JTU
9	4.5	45 JTU	90 JTU
10	5.0	50 JTU	100 JTU
15	7.5	75 JTU	150 JTU
20	10.0	100 JTU	200 JTU