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Ref. No. [UMCES] CBL 2015-014
ACT VS15-07
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Figure 4.
Time series of the Xylem EXO-pH2 test instrument pH results along with the dye reference pH
results for the complete ten week lab test. Results include nine rapid pH transition tests conducted at each
temperature and salinity condition. Detailed plots of each transition test are provided in Appendix I.
Results were further examined for the stable portions of each of the source waters and
these data do not include any of the pH shifts or temperature shifts. For the seawater trials,
salinity was maintained within 0.12 units (range = 35.14 to 35.26) with an average of 35.19 and
temperature was maintained to within 0.8
o
C for each set point (Fig. 5 top). The first temperature
trial ranged from 20.07 to 20.88
o
C, with an average of 20.27
o
C., the second temperature trial
ranged from 9.98 to 10.64
o
C, with an average of 10.12
o
C, and the third temperature trial ranged
from 29.77 to 30.53
o
C, with an average of 29.90
o
C. Time series results of the EXO-pH1,
Metrohm data and reference pH data are shown in middle panel and the time series of the
calculated difference between EXO-pH1 and reference pH are shown in the bottom panel. The
average difference between the EXO-pH1 and reference pH for the stable seawater component
was 0.09 ± 0.04, with a total range of 0.02 to 0.17 (N=59).
Time series results of the EXO-pH2, Metrohm data and reference pH data are shown in
figure 6. The time series of the calculated difference between EXO-pH2 and reference pH are
shown in the bottom panel. The average difference between instrument and reference pH for the
seawater component was 0.07 ± 0.05, with a total range of 0.01 to 0.17 (N=59).