EDTA

EDTA is a popular acronym for the chemical compound Ethylene-diamine-tetra-acetic acid. EDTA refers to a chelating agent that is widely used to sequester di- and trivalent metal ions. (It makes toxic metals non-toxic).

Chelated metals (made non-toxic to aquatic animals) are added to aquarium tanks to fertilise plants.

Typically Zn, Cd, Ni, Cr, Cu, Pb, and Fe EDTA.

Links

 * Wikipedia
 * EDTA - A Molecule with a Complex Story