These data came from a Deep SeapHOx V2 with a CTD that was no longer reporting data. While uncommon, this is usually due to one of the following reasons:
- Exhausted batteries in the CTD
- Disconnection from the CTD
- Improper configuration of the CTD
The Deep SeapHOx V2 requires temperature and salinity data from the CTD to calculate an accurate pH value. When the CTD is absent, the Deep SeapHOx is missing crucial parameters required to convert the raw data from the ISFET pH sensor to a proper pH value. The result is “NaN” values in the CTD data columns as well as the pH External column.
Download our guide to configuring and verifying a drop-in CTD for any Deep SeapHOx V2, or scroll down in the newsletter to access our latest application note to learn how to reprocess pH data from the raw ISFET voltage.