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Both Red Sea systems replace freshwater lost to evaporation, but they are packaged differently. ReefATO+ is a standalone three-in-one product. The newer ReefControl ATO module works through a ReefControl Lite or Pro controller and is included with REEFER G3+ systems. That distinction matters most if you already own an ATO or expect a leak alarm in the new box.
The quick comparison
| Feature | ReefATO+ | ReefControl ATO module |
|---|---|---|
| Controller arrangement | Its own Wi-Fi connected ReefATO+ controller | Connects to ReefControl Lite or Pro |
| Automatic top-off | Included | Included when paired with ReefControl |
| Temperature monitoring | Included | Built into the ATO level sensor |
| Leak detector in the listed package | Included | Not listed with the module; ReefSense leak detector is separate |
| Typical choice | Add a complete ATO to an existing system | Use the ATO in a ReefControl-based setup |
What changes in a REEFER G3+?
The preceding G3 range was supplied with ReefATO+, which Red Sea describes as an ATO, digital temperature monitor and leak detector. Standard G3+ systems instead include ReefControl Lite or Pro with the ReefControl ATO module. The level sensor and pump connect to that controller, so the ATO becomes part of the wider monitoring system.
The new module’s level sensor also measures temperature. Red Sea separately offers a ReefSense digital leak detector for ReefControl. If an alarm for water on the cabinet floor is important, verify that the relevant detector is on your order; the ATO module description does not list one in its box.
Does a G3 owner need to replace ReefATO+?
Usually there is no reason to replace a working ReefATO+ merely because ReefControl exists. It already tops off, monitors temperature and provides leak detection. If you want additional ReefSense monitoring, investigate a separate ReefControl installation while keeping the ATO arrangement clear. Red Sea describes the ReefControl ATO module as connecting directly to Lite or Pro; do not assume a ReefATO+ pump or sensor can simply be plugged into those ports in place of the module. Check the current manuals or manufacturer support before buying components for a conversion.
Practical setup checks
Whichever route you use, keep the top-off reservoir accessible, mount the level sensor as directed, route tubing safely and use the supplied siphon breaker where the installation requires it. Test the water level response and alerts before leaving the tank unattended. An ATO maintains water level by adding freshwater; it does not replace salinity checks or routine maintenance.
For the wider system change, read our REEFER G3 vs G3+ guide. Current accessories are in the Red Sea controller collection; check individual listings for stock and exact contents.
Sources: Red Sea ReefATO+, ReefControl and ATO module and REEFER G3+.
Product specifications can vary by model and package. Check the exact listing and Red Sea documentation before ordering.
