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!