Macherey-Nagel 92110 0-14 pH Indicator Strips 100/Box

I would guess that the resolution of the strips is probably plus or minus one pH value, but that works just fine for when you want you want a rough indication of acidity or alkalinity. Fast and easy. Would use again.

We tried several of the highly rated pH strips for my child's science experiment and these are the only ones we'll continue using. The main issue with all the others has been that liquid would spread the dye from the different squares all over and the colors would get mixed up (shaking the liquid off doesn't really help because everything mixes anyway as you're shaking it off). These pH strips are the only ones where the colors stayed in their own squares and didn't contaminate the others. Consistency between readings has been very good and accuracy has been good as far as I can tell by testing things with known pH. I thought that the color guide was good, too: the colors on the strips faithfully represent the colors on the guide.

I use these strips for making skin care items and they work fine.

I have a quite acidic vegetable fertilizer (kept acidic for long term storage) and I wanted to bring it to roughly neutral pH using a potassium hydroxide (KOH) solution I made from powder, and needed to figure out how much KOH to add. As with all pH test strips, these are nothing like a pH meter, but it was easy to figure out how to get things in the neutral range using these strips.I work in a university research lab, and Macherey-Nagel is a good brand. I would pay considerably more buying it from one of the scientific supply houses than the Amazon price so I am happy with what I paid given these are high quality.

I think these pH strips are relatively easy to match the strip to the container. I returned a different brand because I could not match the strip color to a color on the box. The only thing that I would improve upon would be to include halves. These only include whole numbers. I thought they worked well enough that I reordered.

OK, I'm convinced there are a few dozen people who bought these and don't know how to use them, or don't understand the pH scale. Basically, if you want to measure pH accurately by any method, you need to calibrate your detector, and if you're using these strips, your "detector" is your own pair of good old Eyeballs Mk. 1. Everyone sees color a little differently, even those who are not colorblind, so to read these things accurately, you need to test a few of these strips on solutions of known pH in order to calibrate your color vision relative to the box. I tested these strips at 4.0, 7.0, and 10.0 using known buffer standards, and found that FOR ME, the second color (green) was a little off. Once I knew what to expect (in other words, got myself calibrated), I've found this product to be quite suitable for general lab work. I've prepared buffers using these that have matched both electronic pH meter measurements and gave expected values as predicted by Henderson-Hasselbalch method.

I have tried three brands to test the pH of skin care products that I need to alter with additives, and these are the most accurate and easy to read. Sometimes, depending on what it is, it takes a few minutes to complete changing colors while other times it is correct right away. That is the only difficulty with these. Make sure all 4 colors on strip are the closest match to the box ph #'s, & you will be very close to the correct pH! If you cannot get all 4 colors on the strip to match right off.. give it a few more minutes, and try comparing it to the Chart again- some items take longer than others to get a good read.

I was surprised that a big white sticker was placed over the PH chart. It makes it very difficult to compare my strip against the chart to determine what PH I have on whatever item I am sampling. I tried to peel that sticker off, but it comes off in pieces. It is frustrating, and was a very bad decision by someone.