- Apr 6, 2018
- 21
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Hi all,
Hoping a chemistry guru can help me make sense of something. I’ve been tinkering with a pH meter because I have a hard time differentiating the colors on the drop test, even after switching to a larger 2000-series (44 mL) comparator and R-0004 reagent.
I calibrated the meter today at 6.86, 4, and 9.18. It wasn’t far off at either step, but I calibrated it anyway. Then I tested my pool water and it said it had a pH of 7 while the colorimetric test indicated about 7.5 (blindly confirmed by three people).
I went back to the standards, and the meter was within a few hundredths of matching all three. I tested my tap water and the meter and colorimetric tests agreed at 8. I then tested the 6.86 standard and the meter and colorimetric test agreed on that too. Back to the pool water, the meter read 6.99 and the colorimetric test was clearly somewhere in the 7.4-7.6 range. What gives? Is there something in my water interfering with one method or the other? Here’s what I know I have:
FC 10
CC 0
TA 80
CH 400
CYA 60
Salt 4400
Borates 40
Temp 78 (the meter is supposed to correct for this).
Anything else in the water is unknown. I’ve never used algaecide, clarifier, or anything except chlorine, acid, CYA, CaCO3, NaHCO3, borates and salt.
Thanks in advance!!
Hoping a chemistry guru can help me make sense of something. I’ve been tinkering with a pH meter because I have a hard time differentiating the colors on the drop test, even after switching to a larger 2000-series (44 mL) comparator and R-0004 reagent.
I calibrated the meter today at 6.86, 4, and 9.18. It wasn’t far off at either step, but I calibrated it anyway. Then I tested my pool water and it said it had a pH of 7 while the colorimetric test indicated about 7.5 (blindly confirmed by three people).
I went back to the standards, and the meter was within a few hundredths of matching all three. I tested my tap water and the meter and colorimetric tests agreed at 8. I then tested the 6.86 standard and the meter and colorimetric test agreed on that too. Back to the pool water, the meter read 6.99 and the colorimetric test was clearly somewhere in the 7.4-7.6 range. What gives? Is there something in my water interfering with one method or the other? Here’s what I know I have:
FC 10
CC 0
TA 80
CH 400
CYA 60
Salt 4400
Borates 40
Temp 78 (the meter is supposed to correct for this).
Anything else in the water is unknown. I’ve never used algaecide, clarifier, or anything except chlorine, acid, CYA, CaCO3, NaHCO3, borates and salt.
Thanks in advance!!
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