So you tested 2 days apart 9/9 and 9/11 without any intentional changes between the two.
differences
Unwanted heavy metals : none
Fe-group: none
Trace
Ba 28 and 27 ppb
Si 141 and 168 ppb
P 27 and 19 ppb
Zinc 3 and 1 ppb
Iodine 23 and 14 ppb
Li 199 and 203 ppb
Ni 2 and 2 ppb
Mo 9 and 7 ppb
Majors
Na 10,640 and 11,060 ppm
+3.9%
Ca 431 and 450 ppm
+4.3%
Mg 1285 and 1328 ppm
+3.3%
K 396 and 410 ppm
+3.5%
Br 61 and 63 ppm
B 4 and 4 ppm
Sr 6 and 5 ppm
S 873 and 906
+3.7%
This gives you a good view of the variation inherent in measuring tank water on a day-to-day basis with ICP. For many of these - the majors especially - that variation is not going to be due to your water changing, it's just the day to day variation in ICP measurement process.
Notice how all of the 5 largest concentration elements increased by the same 3.5 to 4%
This is not saying your water evaporated that much in 2 days. This is in line with the day-to-day calibration, recalibration, cleaning etc that happens with ICP.
See this chart from the
article that
@Rick Mathew @Dan_P and myself worked on.
Fritz stored some of their saltwater and had it re-tested by the same vendors. One vendor thought all the majors decreased by ~10%. Triton thought they increased by ~5%. And a third thought they went down ~2%. So it's mostly not sample variation here - just noise in the ICP process.
Overall, that's pretty consistent results compared to some I've seen and I think it nicely puts the yellow warning colors into context, when for a couple of elements - one sample had it, and 2 days later it didn't.