Taylor uses a carefully pH buffered reagent with melamine because melamine cyanurate at normal pool pH is actually soluble to around 20 ppm so you need to force the pH much lower to get an accurate reading. Though I trust Taylor in doing this right, I wouldn't be so sure about cheap test kit brands -- one can check the pH (with wide-range tester -- even test strips is OK in this case) of the mix of pool water with reagent in each case and it should be quite low.