My expedition to the local Bunnings , was interesting but fruitless , the guy knew what I was after , but couldn't find it , as I wandered past the thinners section pricing 20 liter Xylene & Tolulene drums (octance/anti detonation additives) to compare against 200liter drums , I found a 1 litre bottle of liquid Oxalic Acid & cut down to 10% purity & $14 !!!
The instructions said you could step on it further to make 5 liters in total , I never buy product that far down the line , it's always expensicve & heavily stepped no matter what you are buying , so I'll have to go to the Pharmacy for the good stuff, BP.
It did give me a reasonable "working guide" on how to cut & dilute the pure crystal.
I missed reading the safety instructions , they are usually a good guide as to what you are dealing with , Ted seems to be dealing with confused manufacturers ....