@Cory
Thanks, hrm, not sure why mine is not then I am dipping once per second, for 30 seconds and then immediately reading the result, shows zero...but if I let it sit, it will start to darken around the outside edge of the strip to the color I would have expected.
The videos you posted earlier in the thread showing from the lab exactly how to perform the test are no longer working, do you perhaps have a new link to that video?