I have been using the Lamotte Color Q pro since the pool opened in early June. It always gives me a reading for FC in the ballpark want: 1.5 to 2.0 ppm. I also have a Taylor K-2005 kit that uses the pink water color comparison test which I do not use because of the inaccuracy. So a few weeks ago I bought the R-0871 (FAS-DPD Titrating reagent and the R-0870 the powder that turns the water sample pink. I always get a much higher result from the FAS-DPD test than with the Color Q pro. Today the Color Q gave me an FC result of 1.87 ppm. I immediately did the test with the Taylor as follows: fill the large tube up to 25 ml level, cap and mix thoroughly. Then add two scoops powder with the tiny spoon, mix thoroughly and it turns pink. Then added R-0871 titrating reagent to the tube dropwise while counting the drops until the water in the tube turns from pink to clear. I was careful to mix up the water in the tube thoroughly as I went along. Today, I added 19 drops. This is multiplied by 0.2 and the result is 3.8 ppm free chlorine. Does anyone have an opinion as to which one is correct? Am I doing the Taylor FAS-DPD test correctly? The procedure I followed is taken directly from the Taylor website.