HYDROS Control 4 is a larger, more powerful device with all the capabilities of the HYDROS Control 2 plus additional ports to monitor, control, and power equipment. Track temperature, pH, ORP, water level, flow, leaks, outlets and more. Control pumps, timers, level sensors, dosers, fans, solenoids, switches, cabinet lighting, and whatever else you dream up. Made in the USA.


HYDROS is different from other aquarium automation systems. Rather than having a central brain, the HYDROS platform is distributed across devices — each capable of being used on its own or together with other HYDROS products as part of a larger system. This means every HYDROS device is a smart device with its own CPU and scheduling capabilities.

HYDROS devices look like industrial controllers because they are built to function in the harsh environment of a marine aquarium. The sealed HYDROS enclosures and aircraft-style connectors ensure long term reliability in the face of splashes and corrosive salt spray. Why would you use equipment that wasn’t built to survive in the environment it was intended to be used in?


  • HYDROS Cloud, a powerful mobile app to monitor and control HYDROS devices from anywhere in the world.
  • Local monitoring and control via Wi-Fi if a cloud-based configuration isn’t for you.
  • A fast dual-core 32-bit processor that allows control decisions to be made within each device.
  • Internal health monitoring to report voltages, currents, CPU status, and the internal temperature of each device.
  • HYDROS Command Bus connections to transfer data and power to devices.

Most aquarium control systems use many different types of ports to plug in the various sensors we run on our systems. For example, your aquarium controller might only allow a temperature probe to be connected to a dedicated temperature port. But if you wanted to use an optical sensor to measure water level instead of temperature, you may be required to use a different port entirely. Or worse, you might have to purchase an entirely new module to plug in the water level sensor.

HYDROS remedies this problem with Sense Ports that allow you to connect a variety of different types of sensors to a single port type. That way, you always have the right port available regardless of the type of sensor you want to connect.


The Sense Port is an entirely new concept in aquarium parameter measurement. HYDROS devices include several Sense Ports. A Sense Port is a generic input port that can accept data from numerous different types of sensors. 

Sense Ports currently support:

  • Temperature probes
  • Optical level sensors (single and dual)
  • Capacitive non-contact liquid level sensors
  • Rope leak detectors
  • Point leak detectors
  • Flow rate sensors
  • Magnetic switches
  • Push button switches


The Drive Ports provide switched 12V DC power for running small lights, motors, pumps, fans, and other accessories. The exact current being supplied by each port is continuously monitored by the Control 4, so if a motor or pump quits drawing current or draws too much, you will be immediately notified.

Accessories currently supported include:

  • Auto Top-Off (ATO) pumps
  • Cooling fans
  • Cabinet LED lights
  • Solenoids to control reverse osmosis systems


One of the most remarkable ports on the HYDROS Control 4 is the Probe Port. You can connect an ORP or a pH probe to the Probe Port but, this is no ordinary pH input! The circuitry is based on an ultra-high-quality input chip specifically designed for these types of probes. Each pH input provides

digital galvanic isolation from the rest of the system. Galvanic isolation prevents interference with other accessories connected to the system like motors and pumps. Digital Galvanic isolation preserves the accuracy of the measurement by converting the signal to a digital domain before crossing the isolation threshold.

0-10V PORT

The HYDROS Control 4 has 0-10V I/O ports that allow it to control and receive commands from other HYDROS devices and accessories from other brands. A legacy automation system can provide input via the 0-10V Ports. They can control variable speed pumps and can also be used to monitor simple switch closures, like push buttons or float switches.


The HYDROS Command Bus is used to interconnect HYDROS devices together via CANbus. This robust vehicle bus standard allows devices to
communicate with each other without a host computer and was originally designed for use in automobiles and factories. If you’re driving a modern vehicle, you already use CANbus. It’s what turns your brakes on and triggers your airbags to save your life in a car accident.