The Open acidification Tank Controller: An open-source device for the control of pH and temperature in ocean acidification experiments

Kirt L Onthank; James Foster; E Preston Carman Jr; John E Foster; Monica Culler-Juarez; Eliam Calvo; Wesley Duerksen; Trevor Natiuk; Lucas Saca

doi:10.1016/j.ohx.2023.e00435

The Open acidification Tank Controller: An open-source device for the control of pH and temperature in ocean acidification experiments

HardwareX. 2023 May 30:14:e00435. doi: 10.1016/j.ohx.2023.e00435. eCollection 2023 Jun.

Authors

Kirt L Onthank¹, James Foster², E Preston Carman Jr², John E Foster³, Monica Culler-Juarez¹, Eliam Calvo², Wesley Duerksen², Trevor Natiuk², Lucas Saca²

Affiliations

¹ Department of Biological Sciences, Walla Walla University, College Place, WA, United States.
² Department of Computer Science, Walla Walla University, College Place, WA, United States.
³ Department of Mathematics, Walla Walla University, College Place, WA, United States.

Abstract

Ocean acidification is the process by which the increase in atmospheric CO₂ causes a corresponding increase in seawater CO₂ and results in lowering the seawater pH. While this process is likely to have substantial impacts on marine ecosystems, research into the effect of ocean acidification has been limited by the high costs of quality tools to perform ocean acidification treatments in the lab. The Open Acidification Tank Controller is designed to reduce the cost of ocean acidification research by providing a device that can monitor and control pH and temperature of aquaria as well as or better than commercially available research-grade devices, but for less than $250 USD per aquarium. The device is centered around an Arduino Mega 2560 and is assembled into a 3D printed housing. It monitors pH using a BNC glass pH probe and temperature using a three-wire waterproof PT100 temperature sensor. The Open Acidification Tank Controller also features web-based parameter reporting, and data storage to a micro-SD card. This device can hold aquarium pH and temperature at given setpoints, ramp between two values over a user-defined time period, or produce a sine-wave fluctuation in values.

Keywords: Arduino; Lab sensor; Ocean acidification; pH stat device.