Exo Auto Top Off

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Maintain a consistent salinity in your aquarium without relying on failure-prone float switches. Arguably the most time-saving addition to any tank, never worry about your aquarium running dry again. With all internal components built into the optical sensor housing, there are no additional controllers to mount giving a clean and easy to install system. The Exo Mounts easily to clear sump and aquarium walls with internal magnets that securely hold on glass up to 5mm thick. The Reef Breeders Exo ATO system is an ultra-intelligent and compact bundle at an affordable price sure to make your tank more enjoyable.


Intelligent Redundancy:

  • Frequency Alert: The system will beep to notify you that your aquarium has not been topped off for an unusual amount of time, at least 24 hours, and double the average time between Top Off. Ex: if the Avg. time between topping off is 12 hours, the system will notify you after 24 hours of not topping off.
  • Overfill Alert: The system develops and average time that the pump is running each time the system is activated. If the system detects that liquid has been dispensed for more than 3x that average baseline time, it will shut the pump off and create an audible alarm.
  • Empty Reservoir Alert: The system can detect when the top off pump is drawing excess air/running dry and automatically shut the pump off and create an audible alarm.
  • Sensor Obstruction Alert: The system will detect if the in-tank sensor needs to be cleaned, is being obstructed or is out of alignment. This is denoted by a flashing blue light.



  • Power Input - 120V AC, 60Hz
  • DC Pump Max Head - 8 feet
  • Max Mounting/Tank Thickness - 0.2" or 5mm - must be used on clear glass only
  • Internal Dimensions - 1.4"L x 1.4"W x .6"H
  • External Dimensions - 1.75"L" x 1.25"W
  • Warranty - 12 Months
  • Water level detection - Optical
  • Tubing Diameter: 5/8" OD | 1/4" ID
  • Tubing Length: 5 ft


What's Included?

1x Sensor

60" Tubing

1x Power Supply

1x Pump

1x Tubing Holder

More Information
UPC 781307520001
Dimensions (Sensor) 1.4"L x 1.4"W x .6"H, (Pump) 1.75"L" x 1.25"W
Max Tank Thickness 1/5 in.
Included Mounting Magnetic
Control Type Preset Plug & Play (No Controls)
Pump Included Yes
Tubing Inside Diameter 1/4 in. (0.25" / 6.35mm)
Warranty 1 Year
Water Level Detection Optical Sensor
Alarms Audible, Visual
Safety Features Overflow Timer, Run-Dry Protection, Empty Reservoir Alerts, Sensor Obstruction Alerts
Max Head Height 5 -10 Feet
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Product Questions

Can this be used in AIO aquariums without a sump? (Where the back part is basically your sump.) If so, which chamber should it be placed in?
Question by: Reef on Sep 4, 2022, 5:54 PM
Hey there,
Thank you for reaching out to us. Yes, it can, but if you have a black film on the glass, it will need a small portion to be cut off. It should be in the return pump chamber.
Answer by: Matt Lucero (BRS Staff) on Sep 9, 2022, 10:23 AM
On the AXO auto too off can the sensor be submerged? When pump is off, using in a AIO. Same question about the Reef breeders ato.
Question by: Jeff on Sep 11, 2020, 9:57 PM
Yes, the sensor can be submerged.
Answer by: Matt Lucero (BRS Staff) on Nov 5, 2021, 9:49 AM