Apollo SciTech’s AS-pH1 Analyzer has been developed for high precision and accuracy, automated and fast determination of seawater pH. It is based on the principle of colorimetric determination of the relative color intensity using a pH indicator (m-cresol purple) at three wavelengths (434nm, 578nm, and 730nm) with the first two absorptions as a known function of pH, and the third one serves as a baseline correction (Clayton and Byrne 1993; Liu et al. 2011). The automated analyzer is designed according to Carter et al. (2013) with improvements. A high-quality Agilent spectrophotometer (it was Agilent model 8453 or 8454 and is now replaced by model Cary 60) is used for the colorimetric determination and a high precision Kloehn digital pump is used for the delivery of pH indicator and the sample. The system is automated by analyzing a set of 8 samples in about 35 minutes.