--- title: "Dissolved CO₂ Sensors & Monitoring | Aethair" description: "Dissolved carbon dioxide is the CO₂ held in solution in water. See which Eureka Manta+ sondes measure it and how the data is reported." url: https://aethair.io/parameters/dissolved_co2/ --- Measurements · Water Quality # Dissolved CO₂ Also known as dissolved carbon dioxide Dissolved carbon dioxide is the CO₂ held in solution in water. [Schedule a call](https://calendly.com/d/ctdd-mkr-v9v/aethair-demo-website) [Configure Dissolved CO₂ Monitoring](https://aethair.io/build/?params=dissolved_co2) At a glance ppm Water Quality 1 way to measure it - **Thiamis** 1 external instrument What it is ## What is dissolved CO₂ monitoring? Dissolved carbon dioxide is the CO₂ held in solution in water. On this platform it is one of the optional sensors of a multiparameter water-quality sonde, and it has one source: the dissolved-CO₂ sensor of the [Eureka Manta+](https://aethair.io/sensors/eureka-water-probes-water-quality-sondes/) sondes. The dissolved-CO₂ sensor is carried by the larger Manta+ sondes (the Manta+ 35, the anti-fouling Manta+ F35, and the Manta+ 40), which host the full core suite together with fluorometers, ion-selective electrodes, barometric pressure, and depth. The smaller Manta+ 20, 25, and 30 and the fixed-configuration EasyProbes do not carry it. How it is measured ## How Dissolved CO₂ Is Measured A Manta+ connects to a [Thiamis](https://aethair.io/products/thiamis/) gateway over RS-232 using Eureka's Manta ASCII protocol. Each interval the gateway reads the sonde's header row, matches every column by name, then reads the values, so it ingests exactly the sensors configured on that particular sonde. One detail matters when reading the data: the integration ingests the CO₂ sensor's raw electrode signal, in millivolts. The conversion to ppm is done on Eureka's standalone display and is not sent over this protocol, so on the platform dissolved CO₂ is a raw mV trend rather than a concentration. An instrument on Thiamis 1 A third-party instrument connected to a Thiamis gateway, reporting into the same Environet account. ### Every device and option that measures Dissolved CO₂ 1 | Device / option | Type | Base platform | Measures | | - | - | - | - | | [Eureka Water Probes](https://aethair.io/sensors/eureka-water-probes-water-quality-sondes/) · Manta+ 20, Manta+ 25, Manta+ 30… | Water Quality Sondes | Thiamis | Dissolved CO₂ [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Chloride](https://aethair.io/parameters/chloride/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [fDOM / CDOM](https://aethair.io/parameters/fdom/) | [Configure Dissolved CO₂ Monitoring](https://aethair.io/build/?params=dissolved_co2) Related ## More in Water Quality [Water Temperature](https://aethair.io/parameters/water_temperature/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [Turbidity](https://aethair.io/parameters/turbidity/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) Questions ## Dissolved CO₂ FAQ Which Manta sondes measure dissolved CO₂? The Manta+ 35, Manta+ F35, and Manta+ 40. The Manta+ 20, 25, and 30 and the EasyProbes do not carry the sensor. Why is dissolved CO₂ reported in millivolts? The integration ingests the sensor's raw electrode signal. The ppm conversion is done on Eureka's standalone display and is not sent over the Manta protocol. How does the Manta connect? Over RS-232 to a Thiamis gateway, using Eureka's Manta ASCII protocol; the gateway reads the columns the sonde is configured to send.