Quote Originally Posted by john_s View Post
I think I read somewhere that either Calgon is a different product in different countries or that its formulation had changed. Sorry I can't remember where I read it.

Maybe a chemist could suggest an alternative chemical. Would EDTA-tetrasodium salt do it?
I'm an engineer, not a chemist, but according to the chemistry literature, Yes:

EDTA refers to the chelating agent with the formula (HO2CCH2)

Sodium Hexametaphosphate is used as a sequestering agent. It is used in the industry of soap, detergents, water treatment, metal finishing and plating, pulp and paper manufacture, synthesis of polymers, photographic products, textiles, scale removal and agriculture. sodium hexametaphosphate was the sequestrant in the original Calgon product. Phosphates have negative environmental impacts.

sodium tripolyphosphate is a sequestrant

disodium citrate is a sequestrant listed in a current Calgon MSDS

Triethanolamine and Diethanolamine are sequestrants (Fe and Ca).