MagTool Aquarium Auto Top Off System, Green Dual Optical Sensors, 74 GPH Pump

The MagTool ATO Aquarium Auto Top Off System with Dual Optical Sensor-Green automatically replenishes evaporated aquarium water with a 12V DC pump.

• Dual optical water-level sensors — trigger refilling at a low level and stop it at the set high level.
• Compact 0.7-inch (about 2 cm) sensor — takes up little space in the aquarium setup.
• Timed intelligent safety program — monitors fill time and stops operation when needed to help prevent overfilling.
• One-year MagTool warranty and 24/7 customer support — manufacturer coverage and support for the system.
• 74 GPH pump flow rate — moves replacement water from the reservoir into the aquarium.

Evaporation from aquarium lighting, fans, and water movement can lower the water level between manual top-offs. This system is designed to handle routine replenishment automatically, helping reduce day-to-day water additions and the need to ask someone to check the tank during a short trip or business absence. Its dual-sensor control is made to keep the level within the sensors’ operating range rather than relying on a single detection point.

How does the MagTool ATO control water level?

The lower optical sensor detects when the aquarium water drops and starts refilling; the upper sensor detects the target level and stops the fill. This automatic start-and-stop sequence is designed to help maintain a more stable water level as evaporation occurs. A separate intelligent safety program monitors how long filling runs and stops operation when needed, adding a safeguard against overfilling.

• Water-level detection uses two optical sensors.
• The pump runs automatically when the lower sensor detects a drop.
• The upper sensor signals the system to stop filling at the correct level.

Which aquariums is this auto top-off system for?

The MagTool ATO is suitable for reef, saltwater, freshwater, and planted aquariums. It is especially useful for open-top tanks, where faster evaporation can mean more frequent manual water additions. The sensor measures 0.7 inches (about 2 cm), and its low-profile format is designed to take up minimal space and maintain a neat aquarium setup.

• For reef aquariums.
• For saltwater and freshwater tanks.
• For planted aquariums, including open-top setups.

What comes with the MagTool ATO kit?

The kit includes the main parts for daily auto top-off operation, including a 12V DC pump measuring 1.5 × 1.5 × 2.0 inches (3.8 × 3.8 × 5.1 cm). The pump has a maximum head height of 8.2 ft (2.5 m), alongside its 74 GPH flow rate. A 1.5 m water tube connects the water supply path, and the anti-siphon check valve is included in the kit.

• Power adapter and controller.
• Anti-siphon check valve and 1.5 m water tube.
• Mounting bracket and user manual.

The MagTool ATO is suited to aquarium keepers who want routine evaporation top-offs handled automatically, particularly those with open-top tanks or short periods away from home. Its low- and high-level sensing, timed safety program, and included operating components make it a fit for maintaining aquarium water levels with less daily manual topping off.

Read our guide: Aquascaping a freshwater tank: substrate, stone, wood and light