Noticed something interesting with PH testing - Taylor 2006

dykes26

Well-known member
Aug 17, 2009
184
My first test always comes out low- Around 7.2-7.4. I dump it out and refill and this test seems to be accurate. I have run several tests at the same time and only the first comes out low. Am I safe to assume that the second test is more reliable than the first. Thanks in advance for your response.
 

gordiec

LifeTime Supporter
Mar 14, 2009
156
Huntsville, AL
Guess I'll have to try a couple back-to-back pH test tomorrow and see what happens.

Do you rinse your vial out with pool water before doing the first test?
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
20,815
San Dimas, CA (LA County)
When you say you refill it, do you mean you go scoop more water out of the pool for each test, or do you have a container full of water and you just pour some more of the same sample into the test block?

I have noticed that when I get a reading, I set the block aside to do the other tests, and when I look at it again in a few minutes, pH has gone up by about .2
I have been assuming it's outgassing CO2, which is also why I just invert the test block once to mix - no more shaking it. That's also why pH is the very first test I run.
 

dykes26

Well-known member
Aug 17, 2009
184
Refill is a dumping of the old water, flushing it with the pool water and then adding fresh h20 from the pool.
 

gordiec

LifeTime Supporter
Mar 14, 2009
156
Huntsville, AL
Sorry, got home late yesterday so I didn't test the pool until this morning. I did back-to-back pH tests using the Taylor K-2006 kit, both came in at 7.6. I don't know why you get two different readings.
 

PaulR

LifeTime Supporter
Jan 11, 2009
1,966
Cupertino, CA
Do you also test chlorine using the yellow OTO test at the same time? I found that staring at the OTO test will cause some color fatigue. For example if I look at the pH, then at the OTO, then back at the pH--the pH looks like it has gone up, because my eye isn't registering the yellow as strongly. An orange-ish pH result will look distinctly redder the second time.
--paulr
 

dykes26

Well-known member
Aug 17, 2009
184
super! Thanks for your reply. I did some experimenting as well and PH needs to be tested first for a correct first read result. If you check Chlorine first you get a lower ph reading the first time out and a accurate reading the second time through.
 

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