I have never used this model but saw that it gets reviewed well on Amazon 85%: four stars or better.
For those so inclined (or color challenged), a secondary ph testing method (e.g. ph meter, ColorQ)
can be very helpful in getting ahead of the ph test learning curve (ref. color reading, not methodology). I use my ph meter now and then to compare it with the Taylor color block. In a manner of speaking, this allows me to "calibrate" the color reading I am getting on the color block for future reference. Particularly helpful when higher than normal Chlorine levels skew the ph color to produce a color that does not resemble/match anything on the color block (comparator)...typically, a darker red color when pool has higher than optimal CL levels. Parenthetically speaking, who amongst us haven't at some point, questioned or hesitated a little about their ph color interpretation.
FWIW, I gain more confidence about what the ph reading I am taking off the color block is for those times when I don't pull out the ph meter. I have even allowed ph to drift up into the higher levels in order to use the ph meter to ascertain a reasonably precise ph reading, which I then compare to the color block and dial it in mentally for future testing. This because I like to maintain my ph at the higher levels for more ph stability ....and want to ensure I don't cross over it to unacceptable ph levels of + 7.8. Those last to upper purplish colors on the block can be a bit difficult to get a good read or feel for what is the ph level.
It remains the case that many here scratch their heads and question why go to this extra effort to perform what is for them, a cut and dried testing process..which I find to be somewhat myopic or obtuse thinking. So it is that I raise my hat to those of you who, notwithstanding finding little or no difficulty with this testing process, nevertheless make the effort to suggest alternatives to something other than what works for them.