Hello, I have used the TF-100 test kits for many years thanks to everyone here. I got fresh refills for my TF-100 a few months ago. I just opened my pool on the weekend and for some reason, the TA test does not turn red. When I mix the R0007 and R0008 it turns green but as I add the R0009 it never turns red. It gets a dull yellow but never red. This has never happened to me before through many TF-100 refills that I purchased over the years. Any ideas?