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The first thing to test is your tap water.
Fill the larger beaker (mL beaker) between and mL with tap water from the cold water side.
Place the TDS meter into the beaker, and place the thermometer from the kit along side the TDS meter. Turn on the TDS meter (top blue button) and record the TDS reading. Now record the temperature. Remember to estimate to the nearest tenth of a degree. You can use the Fresnel lens magnifier to help read the temperature scale.
The TDS meter is calibrated to be accurate at.0°C. If your tap water is different from.0°C, then there needs to be an adjustment for the different temperature. Look at the math above in the "Math for TDS" section that shows how to do that. Again, if the temperature is over.0 °C, you need to subtract1.% (0.) of the reading for each degree over. If below.0°C, you add1.% of the reading for each degree under. In this example, the reading was mg/L. The temperature was.9°C. That is over.0°C, so we need to compensate for the temperature difference by subtracting. The temperature difference is.9°C-.0°C, which is3.9°C.
compensation x temp difference x reading = correction amount to be added or subtracted
0. x 3.9°C x mg/L=. 1 °C
mg/L -. mg/L =.mg/L rounded to mg/L is the corrected TDS value.
So report both the TDS value that you read off of your meter plus the TDS value corrected for the temperature of your tap water.
Compare the corrected reading you calcu
