I certainly would not use iodized table salt to make up the 50 grams or so of an ersatz Microdol X, but it would take much more than 1 0r 2% of NaCl in the 2 grams of borax in a liter of D-76 to have any measurable effect on that batch. In any case, you don't want salt in soap, as you know if you've been in the Navy or even on a troop ship. (far fetched, of course.) What surprised me most in this interchange about the evils of cheap borax was the 0.89% of impurities allowed in a batch of analytical grade sodium tetraborate decahydrate. What also surprised me was the fact that certain of our resident chemists would make a blanket statement about the unsuitability of household borax without identifying the actual impurities that make it unsuitable. The pentahydrate or the anhydrate could, in some uses, qualify as an impurity when the borax is used as a quantitative analytical reagent, but would have no effect that we could measure or even see. I know, better safe than sorry, but if 99.11% purity qualifies as analytical grade, you could be safe AND sorry without knowing why. Now, if the allowed impurities were known to be photographically inert, like quartz particles, we could tolerate, probably, 95% purity as long as the impurities settled out or dissolved. As you know, I have been using nearly saturated solutions of borax in some developers and have not seen any sign of sediment or colloidal suspension when I use 20 Mule Team Borax. If there are any harmful soluble impurities, they have not shown up in any photographic way.