Sodium Sulfite is almost always used in home mixed wash aid. Within the several chemicals have been shown to have some effectiveness as wash aids, Sodium Sulfite is predominant. I have not seen carbonate listed among them, but can't rule it out since several alkalais are noted as having measurable benefits for washing.
Originally Posted by Anscojohn
One common formula for Wash Aid:
Water 750 ml
Sodium Sulfite (anhydrous) 100 gr
Sodium Metabisulfite 25 gr
Cold water to 1.0 L
Dilute 1+4 for use
I gather sulfite by itself is workable as a wash aid, but do not have solid confirmation of that. Maybe one of our resident chemist experts could weigh in?