I feel as though I have wasted $110 on the ColorQ test kit. I have the TF-100 kit, but have always had trouble reading the ph. I have been comparing my TF-100 kit to the new colorQ kit for 3 days now and every test is off except for the ph and alkalinity. I had heard that the FC and CH should be right, but I'm not having good results. My FC is always lower on the color Q than the TF-100 kit by about 1.5ppm. The CH is always higher on the ColorQ reading 310 compared to 260 on the TF-100. The CYA I expected to be off, and it is too. My TF-100 consistently reads at 60-70 and the ColorQ tells me that my CYA is 96. I think I will try to return it. If I could have spent $110 on a small more compact Ph tester, It would have been ok, but this thing is kind of big to carry around just to test Ph and still have to carry the TF-kit too. I wish I would have never bought it.