pH Test Not Reading Correctly

jobondur

Well-known member
Dec 13, 2009
182
Virginia Beach, VA
I opened my pool this year and my pH tests don't seem correct. The colors that I'm getting don't align with any of the colors on the OTO. At first it was bright red like the original color of the R-0014 phenol red so I figured I just had a very high pH for some reason. I approximated at 8.5 and added roughly 30 oz. of muriatic acid to correct. Now I retest and it's an orangish color that doesn't match anything on my OTO. My R-0014's expiration date is good and it's been stored properly. Any ideas? Is there anything that would make the R-0014 go bad?

My test results are in PoolMath and can be viewed in my profile.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
37,108
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
That is odd. That indicator can go bad but if within expiration should be good.

Try using 4 drops of reagent and see if the colors match better. Be sure you have a white background when comparing the colors.
 

jobondur

Well-known member
Dec 13, 2009
182
Virginia Beach, VA
That is odd. That indicator can go bad but if within expiration should be good.

Try using 4 drops of reagent and see if the colors match better. Be sure you have a white background when comparing the colors.
I tried three drops and its a shade darker than the 7.2 scale on the test (in the orange color spectrum). If I add a 4th drop it turns a darker shade of orange and a 5th drop just turns it even darker orange. So I'm guessing that my pH is in the 7.2-7.3 range.

Gotcha on the white background, but that's definitely not the issue. This test is giving me substantially brighter colors than I've ever gotten in the 8-10 years of using it.

I'm going to get a buddy down the street to let me use his kit later today to see what happens. That will let me figure out if its my water, the reagent, or the color scale on the test kit (maybe its substantially faded). It has to be one of the three (and I'm guessing reagent).
 

jobondur

Well-known member
Dec 13, 2009
182
Virginia Beach, VA
Are you comparing apples and oranges? R-0014 is the pH test. The OTO test measures chlorine. It starts as yellow and works through schoolbus yellow, hunter orange, pumpkin orange, and into shades of brown.

If the OTO test is beyond yellow, you have real high FC.
Real high chlorine reacts with the R-0014 and makes it read falsely high. Accurate pH test during shock levels with R-007?
I'm using the right side of the K-1000 kit (pH testing). I called it the OTO because that's what it's called on TFTestkits website but I was apparently using the term wrong. However it's the same test I've been performing for pH for many years so I know that I'm doing it correctly.

I just checked it again 15 minutes ago and got the same type of readings (see my previous post) and my Cl levels are only at 5 right now, so not high at all.
 
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