Originally Posted by donbga
pH and excessive amounts of oxalate will be a concern. pH will effect color of your print. The excessive oxalate can be taken care of with a little ferric nitrate.
Remember that what you will be measuring is the Sp Gr of that particular ferric oxalate powder mix! It may contain excess edta, ferric nitrate ( B&S did add small amounts) Look for purple crystals. Add you should add some oxalic acid to get the pH set up to help dissolve the ferric powder.
I have had no problem with it. I don't have animals or children in my darkroom as it is a separate building in an commercial / industrial space.
I bought my last batch of AFS through Johnson Mathey, 2.5kg. Last I looked at big bags 25kg it was only a bit more. The first time I bought it I picked up 500g for $50+/-.
Recently sent some off to some one as a kit; without the H2O2. Check with local hair dressers. Bryant Labs out in Berkely was one source that I used and since they have exited the alt world, I would check with Mike at Artcraft. 1 pint will do quite a bit but the cost of getting a gallon is not 4X but only 1.3X or something like that.