Strange TA test

[sypher.mp3]

Hi everyone,

I ran my first complete test today with the TF100. Everything looked good for a pool still shut down. But I was unable to get a TA result. I didnt get a green color when I added 5 drops of R-0008. It was more of a blue. I decided the blue was the color I was looking for, and titrated the R-0009, but after 25 drops, decided to stop. Was my TA really above 250?!

I came inside and ran the test on some tap water and got a result of 60. So what I am thinking is that my TA is actually very very low, and not registering. The blue color I saw was the blue color of the R-0008 solution.

Another question. When I am doing this, am I wanting the solution to change completely clear from green and stay clear? When I tested the tap water, after 6 drops it flashed clear when the drop hit the water, but went back green. Even after 10 drops, it was still flashing clear and going back green. So do I want it to hold clear, or count drops until it flashes clear?

Thanks!

 

[JamesW]

High chlorine or bromine levels will cause the type of interference you are describing. The test usually goes from green to red, but high chlorine will cause the test to go from blue to yellow.

Try waiting for the chlorine or bromine to go below 10 ppm or try adding 3 drops of reagent R-0007 before the test. It's also important to swirl the sample thoroughly between drops. Some people find that using a speed stir is helpful.

What are your other levels?

 

[sypher.mp3]

Thanks for the advice. I am going to test again tomorrow, because I think I read something wrong. I am using a speed stir. TC was 1-2, PH was <6.8. But the water temp is still 57F, and the pump has not ran all winter. I have been adding bleach periodically just to prevent any growth as the weather has been unusually warm. I plan on taking the cover off and cleaning and opening it this weekend. I am suspecting that my TA is actually low.

 

[duraleigh]

Turn on your pump and let it thoroughly mix your pool water before you tyest again.

If your pH still registers below 6.8, bring that up right away using 20 mule team borax until you get it in the 7's.

After your pH is corrected into the mid 7's then you can address TA.

 

[Bama Rambler]

If your TA is really low then your pH will be very low.

I hate to contradict Dave but if your TA really is low, you need to add baking soda first to get it up some and then test and adjust your pH.

 

[duraleigh]

Good catch, bama!

(my associates in the black sedan are outside your home and wish to speak with you)

 

[chem geek]

The TA test normally goes from green to red, but when the chlorine level is high then it goes from blue to yellow. It is not supposed to go to clear. You can add more R-0007 (thiosulfate) to your sample to avoid this interference or you can just note the blue/yellow transition.

If the TA test initially shows red (or yellow), then that implies a pH of 4.5 or lower. In your case, you start out with blue and you never seemed to get to yellow, but then again you weren't looking for that.

 

[JasonLion]

You are primarily watching for a color change, more than any specific color. Some of the non-Taylor tests will go clear at the end when the FC level is high.