I too got a disappointing result. Both my milks spoiled. When I did the test back in 2009, I used CS I made with my own kit (10 ga 9999 silver rods, distilled water, 4-9Volt batteries and a stirrer I made up which gave me clear 10ppm CS at the time). I have since purchased a Silver Puppy (partly because of my disappointing results with this test. I thought my CS wasn't good enough.) I haven't done the test with the Silver Puppy CS yet so I will try that now. I will post back with results. Probably in 5 days.