from what i understand borax can be replace sodium metaborate in some formulas even though it is sodium tetaborate
( in d-23 for example ) and i think ( correct me if i am wrong ) the film developing cookbook says this ..
i don't think there is any harm using grocery / healthfood store bought ingredients if they are nearly the same as
i purchased a bunch of sodium carbonate at a pharmacy and i never saw a difference between what i paid 40$ for
and what i would have purchase at a grocery store for less than 50¢. ( if i knew i could buy sodium bicarbonate and evaporate the moisture out of it
and covert it to sodium carbonate, i would have done this and purchased THAT at a grocery store and saved myself 39.50$ )
not sure if there is a huge difference between grades of ascorbic acid either and i usually buy 1lb for about $6 instead of scientific grade.