reynolds357 said:
I tested again using the 870/871 and my F.C. was 2 and again I had no combined chlorine. Am I doing something wrong, or is there something interfering with one of the tests?
I'm curious about this. So when you tested again and got 2 versus the previous 4, was this on another fresh sample from the pool? If it was, and there wasn't much time between the two, you got the sample from the same depth etc. I would have to say there was some test error somewhere. Not trying to knock you, but this is most likely. Believe me, if you haven't gotten a test error, you haven't done enough testing yet. I've run thousands of all kinds of tests and it happens to the best and most seasoned of us I promise you. For what it's worth, I have compared all the Taylor tests in the TF-100 to the other top suppliers on the market. Honestly, they are superb in every regard, but the most comparing I've done is with the FAS/DPD found in the TF-100. It is amazingly accurate matched against the best color comparators and photospectrometer methods from HACH and Chemetrics. Any time we get a "weird" or a "no way" result in the field, the immediate answer is re-run it, and sometimes once more just to be sure. This is over-kill for a pool you're on top of, especially if you have a good feel for how yours reacts with regular additions. Hopefully this will reassure you or anyone wondering if these tests are accurate to have no doubt they are.