Quote Originally Posted by Rudeofus View Post
Distilled water is easier to get than most chelating agents, and quite cheap, too. Note, that your concentrate targets people who are very low volume developers, so the cost of distilled water should be irrelevant.
That cheap distilled water will eliminate cloudiness. That leaves the Fenton reaction. But the amount of iron will be low, sourced mainly from the sulfite and not from iron pipes, so Fenton's destruction of ascorbate shouldn't be an issue either. So I'm thinking I'll follow Alan's idea and say "if your tap water is hard, use distilled water" and ignore chelation because it won't be an issue for this one-shot brew.

Anyway...
While investigating chelation of iron, I noticed that your link to the table of stability contants shows that:

* Citric acid chelates Fe(III) well, and Fe(II) poorly.
* Salicylic acid chelates Fe(II) well and Fe(III) mediocrely (if that's a word).

Could both be used and get good chelation of all iron? These acids have the advantage of being widely available.

Mark Overton