TF-100 Test Procedures

[Rasalon]

I just received the TF-100 Pool Test Kit, and want a sanity check, before I drive myself crazy.

In addition to the test kit, I also have the LaMotte digital pH tester (recently calibrated), LaMotte pool test strips, AquaChek 4-way pool test strips, and AquaChek TruTest digital meter. As you can see, I am struggling for a consistent test with consistent results.

On the day I received the TF-100 Pool Test Kit, I used this kit, along with all my other testers, to test pH and alkalinity, as I struggle with these the most with a plaster pool.

The TF-100 Pool Test Kit indicated a pH of 7.2 and an alkalinity of 90. All the other tests indicated a pH around 7.8 and an alkalinity around 140.

As the TF-100 Pool Test Kit was new, and as I was unsure if I was interpreting the results correctly, I decided to go ahead and add 1 gallon of muriatic acid to my pool, to drop both the pH and alkalinity.

After 24 hours, I tested the pool water again. The TF-100 Pool Test Kit still indicated a pH of 7.2 and an alkalinity of 90. All of my other tests now indicate a pH of 6.8 and an alkalinity of 110, which is consistent with a gallon of 38% muriatic acid in a 25K gallon pool.

What am I doing wrong with the TF-100 test kit, that all of my tests yield the exact same results? Here is my test procedure:

- Saltwater pool, salt level is at 3200ppm (using LaMotte digital tester in TDS mode)
- Free chlorine is at 3ppm (both TF-100 test and pool strip tests agree)
- I rinse the TF-100 clear container with distilled water
- I rinse the TF-100 clear container with freshly sampled pool water
- I fill the TF-100 clear container to 25mL with freshly sampled pool water
- I add two drops of R-0007, cap, and mix
- I add five drops of R-0008, cap, and mix. Solution is green.
- I add one drop at a time of R-0009, and swirl between drops. At drop #8, the solution turns almost clear. At drop #9, the solution turns a consistent pink, so I stop adding. TA is 9 times 10, or 90ppm

Why is it that all my other test methods (strips, digital reader) register a decrease in TA and pH with the addition of the gallon of acid, but the TF-100 gave me the exact same results both before and after? I want to only have to rely on one test method going forward, ideally the TF-100, but just need to figure out what I am doing wrong. Thank you!

 

[Bama Rambler]

What happens if you add drop 10, 11, 12, etc. of the R-0009?
You keep adding drops till the color stops changing.
Sounds like you stop adding as soon as you see the color go pink. I add till the last drop doesn't make a change and then don't count that one.

Perform the pH test in front of a white background under indirect sun light.

 

[Rasalon]

What happens if you add drop 10, 11, 12, etc. of the R-0009?
You keep adding drops till the color stops changing.
Sounds like you stop adding as soon as you see the color go pink. I add till the last drop doesn't make a change and then don't count that one.

Okay, I just attempted to test that way. At drop 8, the solution became clear. At drop 9, the solution became consistently pink. At drop 10, the solution became consistently darker pink. At drop 11, the solution became even darker pink. At drop 12, 13, 14, and 15, there was no change. So based on that, my alkalinity would be 110 (complete color change) instead of 90.

Perform the pH test in front of a white background under indirect sun light.

I was holding the pH tester in front of a white piece of paper with a daylight white fluorescent bulb behind the paper. What constitutes "indirect sunlight"? Would that be holding the white paper up to a window that does not have sun shining directly through it, or have my back to the window, holding the white paper in front of me making sure my shadow does not fall on the paper?

Thanks for all the help, I think I am finally beginning to get this.

 

[Bama Rambler]

Now you've got it!

I'm not much better with the pH test. I've found it matches my pH meter better if I'm sitting in front of a window where there's indirect sunlight holding the tester several inches in front a piece of white paper. Of course I get the GK's to give me a concensus whenever they're around.

 

[Thinkly]

Total Alkalinity test – TA has a buffering affect on pH, preventing it from moving suddenly. Good TA readings will be around 70-90 for salt pools and 100-120 for normal pools
1. Rinse and fill the clear plastic cylinder to the 25ml mark
2. Add two drops of R-0007 and mix. Then, add 5 drops of R-0008 and mix again. Solution will turn green.
3. Add R-0009 one drop at a time, swirling between each drop. Wipe the tip of the bottle after every drop with a damp cloth. Continue ‘til color changes to red. Multiply the number of drops you added times 10. (11 drops = T/A 110) Record it. TA can vary widely. but a range of 70-120 normally works well.

NOTE: In the presence of high chlorine, initial color may be blue and shift to yellow. Test is still valid.

Based on the instructions I believe you need a color change, from one color to another, yellow or red/pink. The drop that made the change to a COLOR should be counted.

 

[Richard320]

Okay, I just attempted to test that way. At drop 8, the solution became clear. At drop 9, the solution became consistently pink. At drop 10, the solution became consistently darker pink. At drop 11, the solution became even darker pink. At drop 12, 13, 14, and 15, there was no change. So based on that, my alkalinity would be 110 (complete color change) instead of 90.

Clear? Hmmmm. I start green. Then I get a sort of grey color, then sort of maroon, then that red koolaid color. And the koolaid never gets any redder.