I'm glad this topic came up. I've been using Red Sea Reef Foundations alkalinity test kit, and I dislike the color change (mine goes from blue to a light tan to orange, rather than the blue to red/orange shown on the instructions) because I can't easily determine the end point of the reaction. My reagent is not expired. The other tests within the Red Sea kit have a nice distinct color change.
So, you all say to go with the Hanna PPM kit? Any of you use the dKH Hanna kit?