Review on Macherey Nagel 92110 0 14 Indicator Strips by Christopher Todd

I am new to soap making and took these to test my soap. The recipe I use was given by my teacher and it's a tried and tested recipe, but every time I test it with your strips it says it's "11". So I tested the homemade soap I've been using for several years from a trusted supplier. He experienced "11". So I bought some Ph litmus strips from another vendor and tested mine and another vendor's soap. They both ticked "9" (Safe Read). I also tested with a 1% phenolphthalein solution and it was clear on both soaps (a sign of safety). I've retested a few more times with your PH strips and still get the unsafe reading of '11'. Now decide that the strips I received from you must be defective.