I haven't tried the DGP tri-mix Ray, but a blue or otherwise discolored (purple, brown, etc) tungsten tip suggests you may be oxidizing your tungsten from inadequate inert gas shielding. I've run into it on my lanthanated tunsgen when I oxidize it, usually from not holding the TIG torch still during post-flow for long enough. The tungsten needs to stay in an inert environment until it cools off below its oxidation temperature. You also might notice smoke and contamination on your next arc start.

About tri-mix, when I spoke to an someone (can't remember this name at the moment...) at DGP about what tungsten to use for being able to weld a variety of metals including thick aluminum, I was a little surprised that they were totally poo-poo'ing the tri-mix and recommended 2% lanthanated.