These are very disappointing, especially considering that they're made by Hach, whose water sample chemical reagent kits are widely regarded as the best. I only bought these to measure MPS, since I use Cleanwater Blue and non-chlorine shock, and these are about the only test strips I've found that measure MPS. With that said, though, the pH and TA values read significantly lower than my other two reagent kits read. Very disappointingly, the first item listed in the instructions is a warning that the MPS reading ""may be high if chlorine or bromine are present"". So, if you're like 99% of pool or spa owners who use any chlorinating or brominating agent, these will read artificially high. The edges of all of the squares fade almost immediately, and the centers stay a darker color than the perimeter, basically like the reagents on the pads get washed away. The strips themselves are also very narrow, which makes them a bit tricky to grasp. Regarding the MPS tab itself, the color on the strip never matches the printed comparison charts, so they're completely useless for what I purchased them for.
