Whatever they sell at Brownell's I have used it for both coloring and heat drawing for heat-treating parts. When I bought potassium nitrate at the drug store it was white and the stuff from Brownell's is reddish, that's the only difference that I know of. It works great for me.
I have used Brownells niter salts and have used potassium nitrate, both with good results. I too noticed the difference in color and decided to call Brownells. One of their tech guys told me that the only reason they are pink is so that you dont get the niter blue salts mixed up with their regular hot blue salts. As far as it chemical makeup of their niter blue salts, he did not know.
