Low Level Residual Quaternary Ammonium (QAC, Multi Quat) Test Strips, 0-100 ppm [Vial of 100 Strips]

I was hoping for the best and that maybe the other reviewers just didn't read the strips right or use them correctly, but they were right. I tested water from many sources with these test strips from well water to Reverse Osmosis water to commercial store bought Distilled water and no matter the source the readings were always the same. Not possible.Distilled water and Reverse Osmosis water cannot have QUAT of 150ppmJust for laughs I tested my toilet water and got the same readings.Spend your money elsewhere.

These strips are for testing surfaces for residual quats (such as from not rinsing properly) on food prep surfaces and even food itself. I got them to test if my years old disinfectant wipes are still good. They came in at a whopping 30ppm, less than a 10th of the recommended levels for sanitizing surfaces.However, I don't have any fresh ones, so I don't know yet if this is common for this brand or if the low levels are due to age.I did have problems with some of the test pads coming off on the disinfectant wipes, and it seems possible to do that on surfaces as well (you are supposed to wet the test pads with distilled water), but I've also gotten them to work. So dunno,Potency is critical for chemical disinfection, so I'm glad to have this tool for tracing efficacy and contamination.