The chloride (Cl-) ion is a component of salt found naturally in minerals and oceans. Chloride salts are typically soluble in water, and high concentrations of chloride in water bodies can negatively impact fish and aquatic communities.
The sonde chloride probe employs a solid state membrane attached to a conductive wire. When the probe is immersed in water, a potential is established across the membrane that depends on the amount of chloride in the medium.