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Ref. No. [UMCES] CBL 2015-010
ACT VS15-03
The 305 Plus was unresponsive to the small changes in pH during the repeated seawater
test (slope = -0.087, r
2
= 0.35) (Fig. 7). The difference between instrument and reference pH
averaged only 0.011 ±0.012 for the first 12 measurements at temperatures near 25
o
C. The
response appeared to change as temperature was cooled down to 10
o
C, and results for the next
20 matched pairs showed an offset of -0.190 ±0.108.
Figure 7.
Cross plot of Idronaut 305 Plus pH sensor measurements against the dye reference pH
measurements for 32 matched observations during the repeated seawater exposure that occurred on week
ten of the laboratory test. Temperature was varied over the course of 3 days between 26 and 10
o
C.
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