A mechanical float switch can stick, but a dual optical sensor has no moving parts to get stuck open or closed - AutoAqua builds its entire Smart ATO line around that more reliable sensing method. Three configurations cover compact tanks, nano setups, and RO/DI reservoir refilling.
Why Optical Sensors Beat a Float Switch
A float switch relies on a physical float rising and falling freely, and debris, biofilm, or a snagged wire can jam it in either the open or closed position - either overfilling the tank or letting it run dry. A dual optical sensor has nothing to physically stick.
Choosing a System
- Smart ATO Lifter - pairs a dual optical sensor with an AQUA Lifter pump to automatically top off evaporated water, built for compact tanks.
- Smart ATO Nano G2 - a hang-on-back auto top-off system built specifically for nano and pico aquariums under 50 gallons.
- Smart ATO RO - built for a different job than a standard ATO: instead of topping off the display tank, it automatically refills your RO/DI reservoir.
Keeping It Running
The DP-200 ATO DC Refill Pump is a replacement/spare DC pump for AutoAqua auto top-off systems - the part to order if your ATO's pump has worn out or failed.
Setup Tips
- Choose based on what you're actually topping off - display tank (Lifter or Nano G2) versus RO/DI reservoir (Smart ATO RO).
- Always pair with a backup reservoir limit as a safety net against any sensor failure.
- Keep the DP-200 on hand as a spare if your system has been running for years.
AutoAqua Smart ATO systems are available at Marine Concept Supply - order online or pick up at our shop in Wheeling, IL. Shop Smart ATO Lifter, Nano G2, Smart ATO RO, or the DP-200 Replacement Pump, and browse more aquarium automation.
