Another question I have concerns Aqua Mira. I want to start using this as a water treatment, but I notice that solution B consists of phosphoric acid. As a sufferer of uric acid kidney stones, I am on a phosphoric acid restricted diet. A while back I passed a 9mm kidney stone and that is an experience I don't want to repeat. Think of something that big passing through a lightweight bear hanging cord and you'll have some idea of what I went through. The pain was excruciating. Luckily the uric acid stones are round and don't have fishhooks like the calcium variety. A question for the chemists out there: after combining the two chemicals, does any phosphoric acid remain in the mixed solution, or does it change into something that will not be harmful to me?

No reaction is ever driven entirely to completion so there will always be some amount of phosphoric acid remaining. I don't know the actual reaction in Aqua Mira or stoichiometric ratios so I can't tell how little will remain. You might want to try contacting Aqua Mira.