Heinz, these are basically the Kodak formulas. Kodak uses stannous chloride and has for over 20 years. The calgon replacement is commercially available in the Dequest family of sequestrants.

The only difference is the stabilzer in which Kodak uses a proprietary chemical and photo flo as part of the mixture. And, some of the chemicals in the process are only available in huge lots at exorbitant prices.