Table 7. Wavelengths used for Spectrophotometric Determination of Inorganic Carbon Species

Channel	Indicator	Acid Wavelength	Base Wavelength	Reference Wavelength
Seawater fCO2	Phenol red	434 nm	558 nm	700 nm
TCO2	Bromcresol purple	432 nm	589 nm	700 nm
pH	Thymol blue	435 nm	596 nm	730 nm