If a cheapskate is using alternate-sourced borax instead of 'photo grade' (or photo company supplied), for cost reasons, then there will be a limit to how much lab refining the cheapskate is able/willing to spend time/money on. A 4 liter Pyrex beaker probably costs more than some of my other stuff and more than my chemicals combined.

I may be in the cheapskate category, but I'm sure I spent more buying bulk chemicals than I could have buying packages of developer, because I would have more fun with the DIY approach.

I DO find the discussion of the science interesting, however.