A dialysis acid precursor assembly including: a dry dialysis acid precursor composition including sodium chloride, a dry acid and a magnesium chloride 4.5-hydrate (MgCl2.4.5H2O), a calcium salt and at least one of a potassium salt, calcium salt and an anhydrous glucose, and a moisture-resistant container having a water vapor transmission rate less than 0.2 g/m2/d at 38° C./90% RH, wherein the dry dialysis acid precursor composition is sealed in the container.