The only method that provided results that were in agreement
with the head space unit under various conditions of salinity andDC
concentration was the OxyGuard CO2 probe analyzer. The price of
the IRGA used for obtaining the pCO2 percent from the HSU and the
price of the OxyGuard CO2 probe are close, $2495.00 and $2285.00
respectively. However, the calibration time for the CO2 probe at
each salinity level and to adjust to changes in CO2 concentrations
was lengthy, approximately 60 and 20 min respectively. Sampling