LaMotte Water & Soil pH - Manual (Page 7)

TESTING WA TER
TAKING WA TER SAM PLES
Carefully follow the suggestions below for taking water samples.
1. The water sample should be representative of the source and free of
any foreign matter, such as aquatic plants and sediment from the
bottom.
2. The container should be clean and free from particles. Use a plastic or
glass container with a screw cap that is large enough to hold water for
all desired tests.
3. Unless the sample is to be tested immediately, the container should
be filled until it overflows, and then capped. This procedure
eliminates the possibility of getting air bubbles into the sample. A
container which is only half full with water is subject to chemical
changes caused by oxidation while being transported. Generally, the
best results are achieved by testing the water as soon as possible.
4. If the sample is taken from a tap, it is important to let the water run
for several minutes before taking the sample.
TESTING THE pH OF WA TER
1. Use a clean pipet (0354) to fill a test tube (0755) to line 2 with
sample water. (See Figure 3)
2. Add 10 drops of Tricel Indicator (5945). Cap and mix.
NOTE: Hold dropper bottle vertically. (See Figure 4)
3. Hold tube flat against white area of Wide Range Color Chart (1353).
Match sample color to a color standard. Record as pH. (See Figure 5)
7
Fig. 3
Transferring
portions of
Fig. 4
Adding drops
of Tricel
Indicator.
Fig. 5