Unlike traditional glass-electrode pH sensors that need frequent manual calibration to correct reference drift, use special buffer solutions, and have special storage requirements, the ANB Sensors pH Sensor uses solid-state electrochemical sensing technology that self-calibrates during operation. There’s no fragile glass, no liquid reference to dry out, and no special storage requirements. Store it wet or dry, deploy it, and it’s ready to go.

That makes this sensor especially well suited for real-world field use on underwater vehicles, buoys, fixed monitoring stations, and autonomous platforms.

It also enables long-term deployments and networked or IoT-style applications; basically anywhere pH data is needed but frequent hands-on maintenance isn’t practical.

The pH sensor comes in two versions with identical sensing performance but rated for different depths. The AQ5 is rated to 5 meters and has a 3-meter cable, making it a great fit for surface vehicles like the BlueBoat or for surface monitoring on a buoy. The OC300 is rated to 300 meters and has a 1-meter cable, suited for use on an ROV or for deeper-water monitoring.

Both sensors measure pH from 2 to 10 with a resolution of 0.01 pH and accuracy of ±0.2 pH, across a salinity range of 0.1–40 ppt. In addition to pH, they also measure temperature, salinity, and conductivity, include a built-in immersion sensor, and have 8 GB of internal memory for onboard data logging.

The solid-state transducer doesn’t require routine manual calibration and only minimal maintenance. After about 75,000 measurements, a light abrasion of the transducer surface with the included sanding pad is all that’s needed. The sensor tracks this automatically and alerts you when service is due. When the transducer reaches the end of its service life, it’s user-replaceable. Replacements are available here.

Each sensor comes with a pre-installed WetLink Penetrator and mounting hardware for easy installation on the BlueROV2 or BlueBoat. They communicate via RS-485, so a BLUART USB-to-RS485 adapter is required.

Once connected to a vehicle, ANB Sensors’ BlueOS extension lets you view pH and other data in real time, with measurements automatically logged in the autopilot log. Check out the integration guides to help get up and running.