I'm using a Walmart HTH kit for this. Just the block and red drops. I think I have read to do the test in sunlight (sun at my back) and to hold it up in front of a white background to read the result. I have a pretty hard time distinguishing the top three colors, but it is easier when I hold it in front of a white thing. If I hold it a few inches in front, it looks like 7.5. If I put it up against the white thing, it suddenly looks like either 7.8 or maybe even 8.2. When you guys say to hold in front, do you mean right up against, or a couple inches away?
Also, is there a drop test akin to the FAS-DPD test for pH for those of us who have trouble with the color matching?