Dihydrogen Monoxide is also a chemical, a very dangerous one at that, but with care and proper use is perfectly suitable for use in a zip hydroboil.
The citric acid will be fine, ive used it in a water distiller for years, you need quite a bit mixed in with the water boil it for about 30 mins...
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc