CO2 Sensors recommendation

Hi all

Am looking for recommendations for CO2 sensors for an automated grow room.

I have tried prototyping a data logger using two devices already with very disappointing results. The MH-Z19 and an SM300D2. When a pair of either of these are left running, the CO2 readings are typically erratic or different, and tend to loose accuracy as a function of being left on. Basically unusable.

I see even the more expensive units want an environment that resets to ~400ppm regularly: The T6613 continuously monitors the environment and records the lowest values, then uses automatic background calibration (ABC) logic to offset the sensor’s stored calibration. This means the sensor is best used in applications where the environment periodically drops to ambient (~400ppm) CO2 levels.

This is no good for a grow room where we want to be able leave PPM levels at ~1000 for extended periods and have a reliable feedback mechanism for our CO2 generation plant.

Welcome thoughts. Happy with any 5v UART or digital type solution.