Representative Sampling - Hach 2100AN Instrument Manual

SECTION 2,
continued

2.3.10 Representative Sampling

Note: Mix by gentle inversion only.
DO NOT SHAKE.
A representative sample accurately reflects the true conditions of the source from
which the sample was taken. To ensure a representative sample, gently but
thoroughly mix every sample before collecting aliquots (sample portions). Do not
allow particles to settle before making measurements.
Run water for at least five minutes before sampling from a water tap in a
distribution system or treatment plant. When sampling from a body of water
(e.g., a stream, reservoir, clarifier or storage tank), collect at least one liter
(1 quart), and thoroughly mix before taking an aliquot for measurement. If the
sample source is not uniform, it may be necessary to sample several locations at
varying depths, and combine the samples into a single, well mixed composite
sample before measurement.
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