When I perform this test, I do the following.
1) Add a serious scoop of the powder. It's probably 3 to 4 times the amount of the "heaping" scoop in the TFTestKit video on how to do the test.
2) Swirl for 30 seconds or so until the water is a nice hot pink
3) Add R381 one drop at a time until the water turns clear, swirling 5-10 seconds between drops
Now here's where my question comes in. In most of my tests the water will turn clear and stay there for a second or two, but then by the time i put the sample down, grab the next bottle to test for combined chlorimines, the original sample is pink again. How long am I supposed to wait between drops to confirm a true "clear" test reading? 1 second? 5 seconds? 30 seconds?
I only ask because the water first turns clear MUCH lower than I think my FC should be reading, and then it takes a lot of swirling (more than 5 seconds usually but less than 30) to get the pink to show back up so that I can add another drop... I'm really confused on this test. I should also point out that I'm shocking too, so that may have something to do with it.