Total alkalinity test turns blue, not red

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ngc4900

ngc4900

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Sep 29, 2012
87
The Villages, FL
Pool Size
14600
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-15)
Hello,

Please see my Pool Math. I run my FC at about 6 - 6.5. When I do the TA test, I get a “blue” color (never have see yellow) change before I get “red”. I only have add one drop to go from blue to red. On my TF PRO SALT kit instruction card, it does say “in the presence of high chlorine, initial color may be blue and shift to yellow. This test is still valid”. Note, every time I get blue and stop, if I add ONE more drop of R-009 it always goes to the red color.

Questions
  1. What is a “high chlorine” level in order to see this blue color change effect? Is 6.5 high enough?
  2. If my chlorine level is NOT high enough to get the “blue” color change, should I just add the one last drop (turns red) and call it my end point?
  3. In 2015, TEXAS SPLASH noted the following: “ When I had that happen in the past, and was concerned about the TA color changes with high FC, I added an extra drop or two of the R-0007 to help neutralize the high FC and make my test more predictable (green to red/pink). Either way you should be fine as long as you observe and count the drops between color changes”
Should I do this to neutralize the high FC effect?

Thanks
Joe
 
ngc4900 said:
Hello,

Please see my Pool Math. I run my FC at about 6 - 6.5. When I do the TA test, I get a “blue” color (never have see yellow) change before I get “red”. I only have add one drop to go from blue to red. On my TF PRO SALT kit instruction card, it does say “in the presence of high chlorine, initial color may be blue and shift to yellow. This test is still valid”. Note, every time I get blue and stop, if I add ONE more drop of R-009 it always goes to the red color.

Questions
  1. What is a “high chlorine” level in order to see this blue color change effect? Is 6.5 high enough?
  2. If my chlorine level is NOT high enough to get the “blue” color change, should I just add the one last drop (turns red) and call it my end point?
  3. In 2015, TEXAS SPLASH noted the following: “ When I had that happen in the past, and was concerned about the TA color changes with high FC, I added an extra drop or two of the R-0007 to help neutralize the high FC and make my test more predictable (green to red/pink). Either way you should be fine as long as you observe and count the drops between color changes”
Should I do this to neutralize the high FC effect?

Thanks
Joe
Click to expand...
6.5ppm FC is not high.
 
FC of 6 is not considered high. This will not alter your results.

I think you're just seeing the transition from green to red. The test is complete when additional drops do not further deepen the red of the test. Good practice is to add drops until the test is red and the final drop does not change the shade, and then that final drop that didn't affect the color is discounted from the final reading. So, for instance, if you added 8 drops until the test was a deep red and a 9th drop does not change the color further then the test is done and recorded as 80.
 
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Great, thanks so much, I would assume adding extra drops (but not counting them) so as the shade does not change would apply to other tests, ie. CH? Salt? etc?
Thanks
 
Yes, any test that is designed to change from one color to another should follow the same practice. The TA test is especially important for it though since it's sometimes 3 or 4 drops to go from a pink color to the endpoint, and with the TA levels needed to keep things stable in a liquid chlorine or SWG pool that sometimes is nearly half the test.
 
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ngc4900 said:
I would assume adding extra drops (but not counting them) so as the shade does not change would apply to other tests, ie. CH? Salt? etc?
Click to expand...
I just read on here recently that the salt test is the exception to this rule. That test goes to a salmon color and then brick red, you want the salmon. Can someone confirm this?
 
mc2021 said:
I just read on here recently that the salt test is the exception to this rule. That test goes to a salmon color and then brick red, you want the salmon. Can someone confirm this?
Click to expand...
No. Ignore salmon, red, pink, any other fancy name. The salt test is different because itll go from milky white/yellow to BAM red/salmon/pink blob of gooy mess. Itll be so obvious it may startle you the first time you see it. This is assuming you have a smart stir.

If youre swirling by hand then I’m not sure how fast the transition is, but if you keep swirling and it doesnt stay some shade of red then add another drop.
 
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Bperry said:
The salt test is different because itll go from milky white/yellow to BAM red/salmon/pink blob of gooy mess. Itll be so obvious it may startle you the first time you see it. This is assuming you have a smart stir.
Click to expand...
I do use a smart stir and I agree the first change is dramatic, if I do a another drop is darkens even more (looks dark red to me) and stops there. I always assumed the last color change was the endpoint, this test seems to be the opposite. The first color change I see matches the video above too, so that's what I'm going with from now on. Thanks
 
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