PH varies

Fishy1234

Bronze Supporter
Jul 6, 2018
301
Apple Valley, CA
Pool Size
21600
Surface
Plaster
Chlorine
Liquid Chlorine
My question is, I see a trend where my first ph test is often very low 7.0 range and obviously wrong. I recheck and usually get a reading that coincides with the very nice meter. Today I had to check ph 3 times before it was same as ph meter and surprised to see 8.2. Each measurement was higher than the last. Is this common? on going issues with PH measurement lead to the purchase of a PH meter. With that said, I generally use the Taylor kit for measurement but compare it to the PH meter when in doubt.
FC 8, PH 8.2, Alk 80. CH 400. CYA 50
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
31,699
Texas, San Antonio/Marion, South-Central Area
Pool Size
17888
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
Many complain about CYA testing difficulties, but the pH is often more tricky for me. I have a meter, but have found that it can be finicky as well and need calibration, so I usually stick to the drop test. Some folks will try adding 4 drops which helps them to see the color hues better. I find outside light under a bit of covered shade with a light background works best for me. But I go with the initial result after adding the drops and gently shaking the viewer.
 
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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
26,487
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
How are you sampling your water?

Are you cleaning your test vials well in between tests and storage?
 
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kellyfair

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Bronze Supporter
TFP Guide
Jun 29, 2016
4,765
Tampa, FL
Pool Size
7000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Intex Krystal Clear
I use the drop test, four drops instead of 5, and hold it up to my kitchen window. I’m almost always exactly the same color as the 7.6 block, and I call it a day!
 
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Fishy1234

Bronze Supporter
Jul 6, 2018
301
Apple Valley, CA
Pool Size
21600
Surface
Plaster
Chlorine
Liquid Chlorine
Maybe that's the problem, I rarely clean the vial. Usually I do the chlorine test, then PH. I do rinse the vial with pool water after checking chlorine, then check PH. Not sure why I'm getting yellowish color on 1st attemp.
 

mgtfp

Bronze Supporter
Mar 5, 2020
1,026
Melbourne, Australia
Pool Size
66000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Astral VX 7T
Are you using one of those double comparator blocks for pH and Chlorine (OTO or DPD)? And you do the chlorine test first, discard the chlorine sample and rinse the comparator block with pool water (inside the pool or by using pool water from a sample bottle?. Could it be that you contaminate the water sample for the pH test with the reagents of the Chlorine test? Try rinsing a couple of times and maybe take the final sample for the pH test a bit further away from the location where you rinsed the Chlorine vial.
 
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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
26,487
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Rinse the vial well before and after use and do the pH test before the chlorine test. Dry the vial with a paper towel after rinsing before storage.
 
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Fishy1234

Bronze Supporter
Jul 6, 2018
301
Apple Valley, CA
Pool Size
21600
Surface
Plaster
Chlorine
Liquid Chlorine
Are you using one of those double comparator blocks for pH and Chlorine (OTO or DPD)? And you do the chlorine test first, discard the chlorine sample and rinse the comparator block with pool water (inside the pool or by using pool water from a sample bottle?. Could it be that you contaminate the water sample for the pH test with the reagents of the Chlorine test? Try rinsing a couple of times and maybe take the final sample for the pH test a bit further away from the location where you rinsed the Chlorine vial.
Yes I have Taylor k2006. One side is large and other side is small vial for checking CYA level. I use the sample bottle to rinse the vials.
 

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