My understanding is that Sodium Sulfite and HQ are responsible for oxygen consuming property of developers and HCA. Then, here's a question I'm hoping someone can answer. If I were to purchase 5 lbs of Sodium Sulfite (it's cheap) and mix it for use as HCA on as-needed basis, kept in a container that it ships in (for example from Photographers' Formulary), would I still have an issue of powdered form of this component reacting with oxygen and basically "going bad?" I know many on APUG mix their own chemistry. How do you deal with raw chemistry freshness?