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Water Quality Lab
Directions: You will be working as a team to determine which of the 4 samples A, B, C, & D
are: pond, ocean, lagoon, or fresh water samples.
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Copy the following table onto a separate sheet of paper to record your data:
Sailinity pH (Meter)
pH (Chemical)
Ammonia Nitrate
Sample A:
Sample B:
Sample C:
Sample D:
Salinity:
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Be extremely careful, you are using an expensive tool!
1. Rinse your refractometer using tap water between uses to ensure its clean!
2. Lift the plastic covering on your refractometer
3. Using a dropper, carefully place 2 drops of your solution on the glass of the
refractometer
4. Close the plastic covering of the refractometer (the water should not spill out)
5. Hold the refractometer up to your eye, and look into the light to read the
numbers
6. Notice where the blue and white sections meet, read the numbers on the % side
(0-100)
7. Record your salinity for each of the 4 samples on your data chart
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pH Meter:
1. Rinse your pH meter using tap water between uses to ensure it’s clean!
2. Turn your pH meter on
3. Dip your pH meter into your test solution, and wait for a reading
4. Record your pH for each of the 4 samples on your data chart
Chemical Tests:
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Read ALL directions carefully; you are using hazardous chemicals!
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Mark each test tube with a wax pencil using: A, B, C, D
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High Range pH Test: pH measures the acidity of the water. Too much acid dissolves
anything with a shell, and becomes toxic to fish.
1. Rinse all test tubes with fresh water to ensure they are clean
2. Fill each of the 4 test tubes to the 5 ml “fill line” with the labeled solutions (A,
B, C, & D)
3. Add 5 drops of the High Range pH Test Solution
4. Cap the test tube and invert slowly 5 times to mix
5. Match the color of your test tubes to the High Range pH Color Chart
6. Record your pH for each of the 4 samples on your data chart
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Ammonia Test: Ammonia measures the amount of one type of fish waste in the
water. Ammonia is released from the gills, urine, and waste and can become toxic in
large amounts. Toxic ammonia can damage gills and cause breathing problems.
1. Rinse all test tubes with fresh water to ensure they are clean
2. Fill each of the 4 test tubes to the 5 ml “fill line” with labeled solutions
3. Add 8 drops of the Ammonia Test Bottle #1 Solution
4. Add 8 drops of the Ammonia Test Bottle #2 Solution
5. Cap the test tube and shake vigorously for 5 seconds to mix
6. Wait 5 minutes for the color to develop
7. Match the color of your test tubes to the Ammonia Color Chart
8. Record your ammonia for each of the 4 samples on your data chart
DO NOT WRITE ON THIS SHEET! 
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Nitrate Test: Nitrate is produced by beneficial bacteria that converts ammonia into
nitrate. Too much nitrate in the water indicates a buildup of fish waste, and can
stimulate an algal bloom and cause fish disease.
1. Rinse all test tubes with fresh water to ensure they are clean
2. Fill each of the 4 test tubes to the 5 ml “fill line” with labeled solutions
3. Add 10 drops of the Nitrate Test Bottle #1 Solution
4. Cap the test tube and invert slowly 5 times to mix
5. Vigorously shake Nitrate Test Bottle #2 Solution for 30 seconds
6. Uncap your test tube, and add 10 drops of the Nitrate Test Bottle #2 Solution
7. Recap your test tube, and shake vigorously for 1 minute to mix
8. Wait 5 minutes for the color to develop
9. Match the color of your test tubes to the Nitrate Color Chart
10. Record your nitrate for each of the 4 samples on your data chart
After Lab Questions:
1. How did the pH results from the meter compare to the chemical test? (Similar/Not?)
2. A) Which pH test do you think was more accurate?
B) Why?
3. A) Which sample of water was the most acidic?
B) Basic?
4. A) Which sample of water had the most salt?
B) Least?
5. A) Which sample of water had the most ammonia?
B) Least?
6. A) Which sample of water had the most nitrate?
B) Least?
7. Based on your observations & results, list the samples of water in order from the
WORST water quality to the BEST water quality.
8. Predict what you think each sample (A, B, C, & D) is: pond, ocean, lagoon, or fresh.