The printout I got says at the top that it was approved 2/20/82 and reaffirmed 5/12/98. Secreteriat: Photographic & Imaging Manufacturers Association, Inc.
It is part of a series of chemicals used for processing photographic materials. None of the grades of borax that I have seen specs for have even mentioned Potassium, and I have seen a lot of them in the past few weeks, including pharmaceutical grade. Did you really get a guarantee of no Potassium? How would we know where to get the "best stuff"? I see your point about specifications. I have not seen how you know you have satisfied your needs. Do you know for a fact that your borax has been tested for Potassium?
The ANSI Standard claims only to imply a consensus of those substantially concerned with its scope and provisions. It further states "Although the ultimate criterion for suitability of a photographic grade chemical is its successful use in an appropriate photographic use test, the shorter, more economical tests described herein are generally adequate.
It would be a good thing if instead of saying that what would keep one from using the technical grade as specified by the manufacturers must necessarilly keep one from using it for any photographic purpose, to tell us what we more mundane uses we might put it to in the darkroom, especially since that grade has passed the use test over many years in many different developers.