hygger Aquarium Auto Top Off Kit

1 customer review
5.00 out of 5 based on 1 customer rating


Aquarium Auto Top-Off Kit safely keeps water and salinity levels (in marine tanks) stable

Package included:
1 x ATO monitor sensor
1 x External sensor
1 x Water pump
1 x 5.9 ft soft hose
1 x Hose holder
1 x User Manual

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hygger Aquarium Auto Top-Off Kit is a device that monitors and automatically adds freshwater to an aquarium to replace the lost water that the aquarium evaporates. It safely keeps water and salinity levels (in marine aquariums) stable. With a built-in fail-safe to keep the tank from overflowing, all functions are displayed by colored LEDs and warning signals. Ideal for reef aquariums, saltwater aquariums, and freshwater aquariums.
hygger 987 auto top off

Auto Filling

When the water level drops below the detection point of the device, the ATO receives an anhydrous signal, it will automatically control the water pump to refill water via ‘LOWER LIMIT’. When the water level rises to the set position, it will auto-stop adding water via ‘UPPER LIMIT’.

Overfill Protection

The ATO system alerts with a flashing LED light and beeping sound if there is any malfunctioning with the device itself, it uses a top sensor to sense the high water level, and auto shut off the water pump when the water level exceeds the desired maximum top-off level.

Dual Fail-Safe Design

hygger auto top-off kit is composed of a controller and a magnetic suction cup. The magnetic suction cup is installed on the inner side, and the controller is installed on the outer side. It is aligned with the water level line that needs to be detected, and then the power is inserted into the controller and powered on to perform the detection. Additionally equipped with one external sensor that monitors the reservoir’s water level to ensure the pump not running dry as a result of water drying out.
Auto top off modes

DC-powered Water Pump

Comes with a mini DC-powered water pump and a soft hose that can effectively pump water from a bucket/jug with a head height of up to 2 meters. the water pump has a max lift of 4.9 ft, make sure the height from the water pump to the aquarium is not higher than 4.9ft. Vice versa, it can also drain dirty water out of the tank with a 74 GPH flow rate.

Keeps Hose in Place

For rimmed or rimless aquariums up to 3/4 inch, make sure the 5.9ft soft water hose is installed above the water level so it won’t siphon when the pump cuts off.

External Sensors

Installed an external sensor on the reservoir wall, or put it in the reservoir if the tank wall is too thick. With a 5.1 ft cable length, the external sensor should be higher than the water pump, ensuring that the pump does not burn out as a result of water drying out.

How Does it Work

This auto top-off system adopts double optical sensors and is mainly used to monitor water shortage and full water status, and control water pumps and solenoid valves.

Directions for Use

Useful Tips

Change working mode: Press and hold the ‘M’ button until the blue light switches to the yellow light (switch between refill water and drainage mode)

Failure Troubleshooting
Monitor system troubleshooting
All lights flashing and the alarm

    • Inaccurate ATO monitor sensor calibration: Wipe the monitor and the fish tank, remove the external monitor, and set it down horizontally to re-calibrate.
  • Overfill Protection: Remove the ATO monitor sensor, reposition and clean the tank wall.

The Optical Sensor Needs To Be Installed On The Transparent Tank Wall

  • Make sure to place the ATO on transparent and keep the tank walls clean.
  • Place the water hose higher than the water surface to prevent siphoning.
  • Please always keep the ATO internal sensor clean and avoid ripples. Otherwise, the sensor will lose its sensitivity and malfunction, and it is incapable of sensing the water level.
  • Align the inner and outer magnetic suction cups horizontally when installation.

Auto top off installation


  • Keep away from places with bubbles and waves, and place it on a calm water surface that will work normally.
  • Manually press the M button once to pause when refilling the tank.


ATO Monitor x 1, magnetic suction cup, for rimmed or rimless aquariums up to 3/4 inch
Water Pump x 1, DC 12 V 5 W, head max: 6.5 FT, flow rate max: 74 GPH

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1 review for hygger Aquarium Auto Top Off Kit

  1. Thin

    So easy to install. Has a plethora of settings and warnings. It wont let the pump run dry to burn it out and its also great for keeping a tank(or sump) at the same water level

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