Soft Opening: Try our new website.

ATO Systems & Reservoirs for Aquarium Plumbing

What does ATO stand for? An ATO is an Auto top off system.

Stop pouring water into your tank every day! Heat and water circulation cause aquarium evaporation. The most basic aquarium ATO is a float switch, which turns on a pump to replenish water lost to evaporation.

There are many advanced ATO systems, like the Auto Aqua Smart ATO or JBJ ATO, that use multiple water level sensors. When the water level drops, the ATO sensor turns on a pump sitting in an ATO reservoir. A good ATO will incorporate at least two sensors as a failsafe, so that a sensor failure doesn’t lead to an overflow. For example, the Tunze Osmolator (a best seller) has a mechanical float, an optical sensor, and an electronic failsafe. All of the sensors must fail for there to be a flood.

Use a kalkwasser reactor along with your ATO to raise pH and replenish calcium and alkalinity.
46 Results
ReefBreeders Prism ATO Auto Top Off System
new

ReefBreeders Prism ATO Auto Top Off System

XP Aqua Duetto ATO Auto Top Off System

XP Aqua Duetto ATO Auto Top Off System

Tunze Osmolator 3155 ATO Auto Top Off System

Tunze Osmolator 3155 ATO Auto Top Off System

Tunze Osmolator Nano 3152 ATO Auto Top Off System

Tunze Osmolator Nano 3152 ATO Auto Top Off System

Neptune Optical Sensor w/ Magnetic Mount for Apex FMM

Neptune Optical Sensor w/ Magnetic Mount for Apex FMM

Neptune ATK V2 Auto Top Off Kit

Neptune ATK V2 Auto Top Off Kit

Neptune Systems PMUP v2 Practical Multipurpose Utility Pump

Neptune Systems PMUP v2 Practical Multipurpose Utility Pump

Tunze Osmolator Replacement Metering Pump

Tunze Osmolator Replacement Metering Pump

Tunze Osmolator Storage Container 27L (7.1 Gal) ATO Reservoir

Tunze Osmolator Storage Container 27L (7.1 Gal) ATO Reservoir

HydroFill ATO Reservoir - Innovative Marine (5 Gallon)

HydroFill ATO Reservoir - Innovative Marine (5 Gallon)

JBJ ATO Automatic Top Off System Water Level Controller

JBJ ATO Automatic Top Off System Water Level Controller

HydroFill Auto Top Off ATO Controller - Innovative Marine

HydroFill Auto Top Off ATO Controller - Innovative Marine

IceCap Auto Top Off ATO

IceCap Auto Top Off ATO

Seachem Hydro Tote Collapsible Water Jug

Seachem Hydro Tote Collapsible Water Jug

Innovative Marine HydroFill Ti ATO Return Pump

Innovative Marine HydroFill Ti ATO Return Pump

Innovative Marine HydroFill Ti Universal Auto Top Off ATO Return Bracket

Innovative Marine HydroFill Ti Universal Auto Top Off ATO Return Bracket

XP Aqua Ultimate ATO - Complete 4-Sensor Aquarium Auto-Top-Off System
15%
off

XP Aqua Ultimate ATO - Complete 4-Sensor Aquarium Auto-Top-Off System

Tunze Nano Osmolator Auto Top Off with 7.1 Gallon ATO Reservoir

Tunze Nano Osmolator Auto Top Off with 7.1 Gallon ATO Reservoir

Marine Depot Standard Float Switch for Auto Top Off ATO

Marine Depot Standard Float Switch for Auto Top Off ATO

Tunze Osmolator Auto Top Off with 7.1 Gallon ATO Reservoir

Tunze Osmolator Auto Top Off with 7.1 Gallon ATO Reservoir

Loading...