Originally Posted by Fletch78
Does K metabilsulphite make sulfate?
S2O5-- + 2H2NCl + 3H2O --> 2SO4-- + 2Cl- + 2 NH4+
but as there generally isn't that much chloramine in water the additional amount of sulfate is not that great. The maximum allowable chloramine is 3 mg/L as chlorine and if that amount is present 8.1 mg/L sulfate would be added to the water if enough metabite were added to completely convert it. This could be appreciable for, say, Bohemian Pils where you wouldn't want the total sulfate to be more than about 15 mg/L but in most cases it wouldn't be significant. Besides which the chloramine level is generally less than 3 mg/L. Excess metabite stays in solution as sulfite which is not detrimental in the same way as sulfate.