The GLOBE hydrology protocol for alkalinity is a tablet-liquid test kit (LaMotte model WAT-MP-DR). Since elementary students are doing the testing under the supervision of a trained adult, the chemical names are left out and colors are substituted. Furthermore, preliminary samples from local surface water show little or no P Alkalinity; thus, use of the white tablets is ignored and total alkalinity is found as parts per million (ppm) as CaCO3.
The resulting simplified procedure is as follows:
Clean, rinse, and fill sample tube to 5 ml line with water to be tested. |
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Add one black tablet from the dark colored bottle with the black cap. Shake or swirl until tablet dissolves. Solution will turn green-blue. |
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Fill the syringe to the '0' line with the solution from the black capped plastic bottle. |
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Cap the test sample tube with the plastic cap and insert the syringe without pushing the plunger. |
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Add one drop at a time and swirl the test sample tube. Watch for a color change to pink. Stop. Read the scale at the plunger tip being careful to calculate the division scale marks. |
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If more than one syringe full is used , add the total solution used in both syringes (i.e. 200+......). Total Alkalinity is the direct result of that reading in ppm. |