pH Test Strips 0-14

I think these ph test strips work well. I tested them out on distilled water, tap water, white vinegar and soduim hydroxide solution. There was not much of a difference between the distilled water and the tap water as expected with a ph of around 7, but the vinegar showed up at about 2.5 where it was supposed to be and the soduim hydroxide solution clearly showed a ph of 14 as anticipated. It also helped me determine that the soap I made did not have soduim hydroxide pockets (lye pockets) in it from under mixing or improper measuring and that the soap was safe to use. You do need to make sure that all four of the squares get fully dipped into the solution you are testing though. That is just how these strips work.

I recently purchased several different ph test strips for my daughter to use for a science fair project. These are the absolute best and most accurate of the test strips I bought. They are as accurate as test strips can be.The colors don't run, unlike some of the others I tried. And they measure in increments of 0.5. They read what they should for the solutions I tested these with (a mixture of water and baking soda for a basic test, vinegar for an acid test, and Evian water for a neutral test since Evian is bottled to be consistently around a ph of 7.2).For those of you trying to use these or any strips to test ph of water, please be aware that all ph test strips will be inaccurate for *most* waters, unless you take special steps (see below). Most bottled water, as well as most tap water, is low ionic strength. Test strips for ph do not work well for low ionic strength liquids (even the ones that say for water). There are some exceptions. Mineral and artesian waters, such as Evian, are higher in ionic strength due to much higher levels of total dissolved solids. For these waters, ph test strips will work fine without altering the testing procedure, including those that indicate for saliva and urine testing only.Some reviews complain about accuracy due to testing with distilled water and not getting a reading of 7.0. Distilled water has nearly 0 total dissolved solids. No ph test strip will work under those conditions. Most mineral waters and artesian waters will tell you on the bottle what its ph is. E.g. Evian claims 7.2. These test strips give a reading of 7.0 in this case and you can't get closer with 0.5 increments.For these strips, or any strips, to work, the total dissolved solids must be greater than 150 ppm. Most mineral waters have at least 220 ppm total dissolved solids, and will have it listed on the bottle, which is why these test strips work in this case.If you need to test ph of low ionic strength waters, such as distilled, tap, most spring waters, then you'll probably need test drops or a meter instead. If you really want to try ph test strips for these waters, there are 2 things you can try. First, you can try soaking strip in water longer such as 30 to 60 seconds instead of 2 to 3 seconds. Second, and more effective, you can try dissolving a neutral salt to increase total dissolved solids. Potassium chloride KCl should work which you can purchase as a solution. Table salt, sodium chloride, should also work, but look for one that is plain salt without anti-caking ingredients and without iodine. Check the kosher salts wherever you buy groceries. Neutral salts won't change the ph of the water, but will increase total dissolved solids. Obviously don't drink the sample you test if you use this approach.

I am trying to extract calcium citrate from egg shells using lemon juice . I used these strips to find the ph of the solution before and after the egg shells have dissolved in the lemon juice (acid). Works well.At first I thought the entire strip will change color. But it is actually 4 squares at one end that change color. You compare these 4 squares as one unit to the squares on the box to determine the ph.

I used these to test the pH of several samples of river water for a school science project. They are a little tricky to read because the colors are so similar, but when compared to other pH strips I would say they are accurate enough. If you are looking for very accurate readings, I would purchase an electronic meter, but these are good enough for science projects and such.

Quick shipping. Not sure if I got a faulty box or if these just dont work but everything tests to 7.5... even tap water.