I'm currently lowering my TA with PH lowering and aerating and I have a question about my testing methods. I have a speed stir with my TF-100 kit and when it's dropping in 009 reagent (wiping between drops), there is a transition period between green and slight pink were it's a faint tint of purplish grey. Usually the next drop makes it a very faint pink and the following drop makes it a bright pink (like when adding in 871 to test for FC). My question is at what "phase" do I consider the shift to occur and stop counting drops? It says when turns from green to red, but there is that purplish grey and then faint pink ... should I be going till it's solid pink (no faintness) and stop or should I be stopping at the faint pink and consider that the shift point?