- May 23, 2015
- 25,693
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Interesting. Looks like a small company out of Florida offering testing chemicals. Funny though if you look at their website they do not ship the borate testing to residential addresses. Only to commercial companies

Anyway, the test that they are using is a phenolphthalein indicator based test where you are looking for a clear-to-pink transition. For phenolphthalein, that typically occurs at a pH of about 8.2 which is a little high for the borate-mannitol test. The test in this thread uses bromothymol blue (BTB) which is a yellow-to-blue transition and that occurs right around 7.4. Both tests have a tendency to slightly overestimate the boron concentration but the BTB is a little closer to the mark. One would ideally do these measurements in a laboratory using a electronic pH probe and a proper titration setup, but since that's a bit overkill, either test method will work "well enough".
If you don't mind spending the money and giving the test kit a whirl, I say go for it and see what you get. Worst that will happen is you'll be out $30...