The Open acidification Tank Controller

Open-Acidification TankController is an open-source Arduino-based system that controls and monitors pH and temperature in research tanks via Ethernet.

Aimee0

Published December 16, 2025

123 UCC

25 WCC

29 VAR

Original source (new tab)

Components

Hardware components

WIZnet - W5100

x 1

Project description

📌 Overview

The Open-Acidification TankController (Zenodo v21.09.1) is an open-source controller project (Arduino + web GUI) designed for ocean acidification experiments. It maintains and modulates tank pH and temperature to target values (including ramp and sine-wave profiles), provides web-based status reporting, and logs data to a microSD card.

The core problem it addresses is that expanding experimental scale is difficult due to the high cost of research-grade equipment. As clearly stated in the related paper and external articles, the project aims to deliver research-grade control at a much lower cost—with a target of under $250 per tank compared to commercial systems.

📌 Features

Precise pH and Temperature Control: Maintains tank pH and temperature at setpoints or varies them over time using experimental profiles such as ramps and sine waves.
Web-Based Parameter Reporting with API Support: The device operates as a “Device Web Server,” providing data through documented endpoints such as /api/1/data and /api/1/display.
MicroSD Logging: The device can store data on a microSD card, ensuring data traceability for long-term experiments.
Arduino Library Manager Installation Workflow:
Official documentation provides a clear procedure in which users search for and install TankController via the Arduino IDE Library Manager, then upload the firmware using the provided example sketches—highlighting strong reproducibility and ease of deployment.
Tank Controller Manager (TCM) for Multi-Tank Operation: A separate management software is provided in a dedicated repository to remotely monitor, operate, and integrate multiple controllers. It is implemented using Flutter (Dart) and is specified to run across multiple platforms.

📌 System Architecture

Local Control (Per-Tank Level)
An Arduino Mega 2560 serves as the core controller, reading pH and temperature sensors and regulating actuators such as CO₂ solenoids and heaters/chillers to maintain target setpoints.

Network (Remote Access & Monitoring)
The device operates as a web server (API), and the README describes DHCP attempt/fallback behavior, allowing it to adapt to on-site network environments.

Data Storage & Operation
Data are logged locally to a microSD card for offline robustness, and the installation documentation includes an optional PushingBox Identifier configuration for periodic cloud data transmission.

Multi-Device Integrated Operation (Lab-Scale Expansion)
The Tank Controller Manager (TCM) is described as providing over-the-network access to multiple controllers, enabling centralized monitoring, operation, and data reporting across many tanks.

📌 Role and Application of the WIZnet's Chip

The project is based on an Arduino Mega and operates a network web server/API with DHCP support. Each device provides URL endpoints in the form of /api/..., and all network communication is performed using the HTTP protocol.

For laboratory equipment, long-term stable operation and deployability/reproducibility are critical. Using hardware TCP/IP reduces the networking burden on the MCU, making the design more robust and allowing developers to focus on control logic rather than network stack implementation.

📌 Market & Application Value

Applicable Industries / Markets

University and research institute marine, fisheries, and environmental laboratories:
Require precise pH and temperature control across multiple tanks, with long-term operation and reliable data logging.
Education and maker-oriented experimental equipment:
The Arduino IDE + Library Manager installation workflow is well suited for educational environments.
Commercial tanks and aquaculture support (expandable potential):
Although the primary focus is research, the combination of precise control and remote monitoring can be adapted to aquaculture and ornamental tank automation (with the caveat that commercial safety, certification, and security requirements would need to be addressed separately).

Productization / Service Expansion Potential

Beyond a single controller, the system already proposes a structure for integrated operation of multiple devices through the Tank Controller Manager (TCM), giving it a strong advantage for scaling at the laboratory level.

Competitiveness Compared to Existing Approaches

As clearly stated in related papers and external descriptions, the project aims to deliver functionality comparable to—or exceeding—that of commercial research-grade equipment at a significantly lower cost, including web-based reporting, SD card logging, setpoint control, and programmable control profiles.

📌 External Indicators

Zenodo

https://zenodo.org/records/5508206

Github

https://github.com/Open-Acidification/TankController

Ongoing releases:
Recent tags such as v25.4.1 are available on the Releases page, indicating active and continuous maintenance.

News

https://news-oceanacidification-icc.org/2023/06/05/the-open-acidification-tank-controller-an-open-source-device-for-the-control-of-ph-and-temperature-in-ocean-acidification-experiments/

The device was featured on the OA-ICC (Ocean Acidification International Coordination Centre) news stream on 2023-06-05, where it was introduced as a solution offering low cost, web-based reporting, SD card logging, and profile-based control.

📌Reference Link

Research: https://pmc.ncbi.nlm.nih.gov/articles/PMC10276295/

Open Source: https://github.com/Open-Acidification/TankController

Homepage : https://open-acidification.github.io/

📌 QnA

Q1. Why does this project use the WIZnet W5100 instead of Wi-Fi?

For laboratory equipment, stability and reproducibility are more important than raw speed. The W5100 handles TCP/IP internally and provides 4 hardware sockets and a 16 KB buffer, allowing the MCU to focus on sensing and control tasks. In addition, the assembly guide explicitly specifies the Ethernet Shield v1 (W5100) as the default component, which improves documentation quality and reproducibility.

Q2. How is the W5100 connected to the Arduino Mega 2560?

The project assumes a stacked configuration of Arduino Mega 2560 + Arduino Ethernet Shield v1 (W5100). During assembly, instructions are provided to insert the board at a slight angle so that the USB and RJ45 ports align with the enclosure openings. The guide also includes wiring instructions to connect the reset button to the Ethernet Shield’s GND/RESET pins, reducing the risk of wiring errors compared to custom cabling.

Q3. What exactly does the W5100 do in this project?

The W5100 integrates the Ethernet physical layer (10/100 MAC + PHY) and the TCP/IP stack, enabling the controller to connect to the network and perform socket-based communication. In the codebase, folders such as Ethernet_TC and EthernetServer_TC indicate a structured approach where network initialization, server handling, and response processing are managed separately.

Q4. Can beginners follow this project?

Yes. The hardware is based on a well-documented, standard combination (Arduino Mega + Ethernet Shield v1), and the assembly guide walks through every step—from the parts list to wiring details (including the reset button). Additionally, the Arduino Ethernet library officially supports W5100-based shields, making debugging easier using standard network examples.

Q5. What would change if the W5100 were replaced with a W5500?

The W5500 offers higher specifications, such as 8 sockets, a 32 KB buffer, and SPI speeds up to 80 MHz, making it better suited for multiple connections or higher traffic. However, this project’s assembly documentation is built around the W5100 shield (v1). Switching to a W5500 would require reviewing shield compatibility (e.g., a W5500-based shield) and library support. In this context, configuration consistency matters more than raw performance.

📌 Summary

The Open-Acidification TankController is an open-source controller designed to automatically regulate pH and temperature in experimental tanks for ocean acidification research, while enabling network-based monitoring and data logging of experimental conditions. By combining Arduino-based hardware with a web interface, it provides stable environmental control suitable for long-term and repetitive experiments.

In addition, multiple controllers can be networked together to enable integrated management of multiple tanks, allowing both experimental scale-up and operational efficiency. With its ability to deliver automated control and remote operation at low cost, this project serves as a highly valuable reference for research and educational environments.