In this study, the HSU with an IRGA described by Watten et al.
(2004) was evaluated for saltwater recirculating system application
and its performance was compared to alternative methods of DC
measurement. The alternative methods included standard methods
of titration, nomographic, and calculation (APHA, 1998), use of the
portable CO2 meter by OxyGuard, and an indirect method using a
pH and pCO2 correlation curve.