Well the end product has to be Sodium Citrate, School Chemistry acid and base reaction, and the behaviour and characteristics of the solution are identical to that made up from a pack of deox C powder, marketed by BILT HAMER Laboratories, added to water....... Got me thinking!
Joking apart, this product does work, so much so that it is advisable to check frequently on its rust removing progress. There may be more rust than you think, and a lot less of the component you put in the bath.
Swarfy.