Welcome to the future of Aqurium automation
Marine Assistant is a next-generation reef aquarium controller designed specifically for hobbyists who want powerful monitoring, advanced automation, and professional-grade protection for their marine aquariums.
Built around the flexibility of Home Assistant, Marine Assistant combines dedicated aquarium hardware with one of the most capable automation platforms available today. The result is a highly customizable control system that can monitor critical life-support equipment, automate routine maintenance tasks, and alert you immediately when something requires attention.
Whether you operate a nano reef, mixed reef, SPS-dominated system, or a large fish room, Marine Assistant provides the foundation for a reliable and intelligent aquarium management solution.
What does it do?
Marine Assistant is a DIY reef aquarium controller featuring dedicated aquarium hardware and seamless Home Assistant integration.
The controller provides monitoring, automation, alarm management, and equipment control through a combination of onboard electronics, intelligent sensors, and customizable software.
Unlike traditional proprietary aquarium controllers, Marine Assistant leverages the power of Home Assistant to give users complete control over how their aquarium operates, looks, and grows over time.
Marine Assistant can:
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Monitor aquarium equipment and sensors
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Control pumps, relays, and accessories
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Detect leaks and abnormal operating conditions
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Manage Automatic Top-Off (ATO) systems
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Monitor water quality probes
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Generate visual and audible alarms
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Send remote notifications
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Provide historical data logging and graphing
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Connect to Wi-Fi for remote access and monitoring, Ethernet also onboard
Why Marine Assistant?
Marine Assistant was designed from the beginning to work with Home Assistant because it offers capabilities that traditional aquarium controllers struggle to match.
Home Assistant is an open-source automation platform that prioritizes local control, privacy, reliability, and extensive device integration. It supports thousands of integrations and allows users to create anything from simple equipment schedules to advanced fail-safe automation systems.
Benefits for Reef Aquariums
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Critical aquarium functions continue operating even if internet access is unavailable.
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Create sophisticated rules, conditions, timers, and safety routines.
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Monitor and control your aquarium from anywhere
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View trends, graphs, and historical performance data.
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Receive alerts by phone, tablet, email, or messaging services.
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Add new devices and integrations as your system grows.
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Open Platform - No subscription fees or vendor lock-in.
Custom Dashboards
Complete freedom to create a Dashboard showing exactly what you want to see and how you see it.
Create different dashboards for different devices... one for your phone, one for a wall mounted display..... All presenting the information differently.
The possibilities are endless!
System Features
Sensor Monitoring
The controller supports a wide range of aquarium sensors:
Float Switches - Water level monitoring, ATO safety
Optical Sensors - Precise water level detection
Temperature Sensors - Aquarium and sump temperature monitoring
Flow Sensors - Return pump and reactor monitoring
Leak Sensors - Flood and spill detection
Echo Sensors - Reservoir volume measurement
Equipment Control
Marine Assistant provides direct control of external devices through integrated 12V outputs, Supported Devices:
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Dosing pumps
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ATO pumps
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Solenoids
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Cooling fans
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Cabinet lighting
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Status indicators
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Digital LED devices
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Custom accessories
Water Quality Monitoring
Dedicated isolated probe interfaces are included for advanced water chemistry monitoring, Supported Probe Interfaces:
pH - Acidity and alkalinity monitoring
ORP - Oxidation Reduction Potential
EC - Electrical Conductivity
TDS - Total Dissolved Solids
DESIGN NOTE
Probe interfaces are electrically isolated from the main controller electronics to reduce noise and improve measurement stability.
The vision for Marine Assistant
With Marine Assistant, We wanted to create something that was easy to build without compromising on features. While testing other reef computers, we noticed room for improvement. The first was the price—many of them come at a premium cost, making them inaccessible to some hobbyists. The second was the lack of third-party sensor compatibility.
Marine Assistant is designed to work with a wide range of manufacturers. Whether you want to spend €30 on a pH sensor from eBay or €200 on a lab-grade sensor, Marine Assistant can be adapted to work with both. You're not locked into any specific sensor system—use whatever works best for you. That being said we provide some recommendations for analog sensors that our guides are based on.
By using Home Assistant for the software, Marine Assistant benefits from continuous development and updates. Home Assistant is a widely used and well-supported automation platform, making it perfect for this application. You can create your own automations and dashboards easily, customizing them exactly how you want. Everything runs locally on your home network, so no cloud service is required (One is however available).
We've also created step-by-step online guides to walk you through the entire process—from building the hardware to installing and setting up the software, adding sensors, configuring automations, and customizing your dashboard.
We are constantly developing this project, working on new hardware and improving the software. With many ideas for the future, including lighting control, dosing pumps, and more.
How much does a set-up cost?
One of the biggest advantages of Marine Assistant is the cost savings compared to the competition—leaving you with more money for livestock.
Here’s a breakdown of the approximate cost of the parts needed to build a basic setup:
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Marine assistant Controller 350€
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Temp sensors 15€
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Flow sensor 25€
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Optical sensor 20€
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Leak sensor 15€
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Ph Kit (DF Robot) 50€
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ORP Kit (DF Robot) 75€
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EC Kit (DF Robot) 70€
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TDS kit (DF Robot) 10€
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Various wire 30€
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12v Power supply 20€
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Various 3d printed parts 20€
Total of aproximatly 700€ for a full setup!!
As for 240v monitoring and switching we take advantage of the home assistant system, use either wireless socket plugs (Tuya for example) or if you prefer a hard wired solution use the shelly system. (shelly 4pm is hard wired, has ethernet and switches/monitors 4 sockets for aproximatly 100€)
All prices are estimates and serve only as a guide to the potential cost of a simple but complete setup. The final price may vary depending on the type and number of sensors you choose.
Essential Skills Can you build one?
Don’t worry—putting everything together is straight forward, even if you don’t have a lot of experience. While a few standard tools are required, the process is simple and manageable. To make things even easier, we’ve put together a wide range of detailed guides and resources right here on the website. Whether you're starting from scratch or just need a quick reference, you'll find all the support you need to get the job done with confidence.
Tools you will need:
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Soldering Iron (Tip should be about 1mm, not too big)
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Solder (Its better to use a good quality one with flux)
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Solder wick or solder sucker (For clean-up)
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Tape (Masking tape or similar)
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Some basic tools. (Screwdrivers, wire cutters.....)
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Multimeter
Optional:
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Helping hands (To hold the PCB while soldering)
Need Help?
Marine Assistant is proud to have an ever-growing community of passionate DIYers who use and trust our hardware for their reef aquariums. Whether you're just getting started or tackling something more advanced, you're never alone. If you run into questions or need advice, feel free to reach out directly—we’re always happy to help. You can also connect with fellow users, share your progress, and get support through our active community group. Join the conversation and become part of the Marine Assistant network, Click below to get involved.
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