Tunze Osmolator 3 Auto Top Off

Never chase salinity swings again. The Tunze Osmolator 3 automatically replaces the fresh water your aquarium loses to evaporation, holding your water level, and with it your salinity, rock steady around the clock. An optical sensor watches the level and the quiet Turbelle high-jet metering pump tops off exactly what is needed, drop by drop, for tanks from 5 to 180 gallons.

It is the full-size sibling to the Osmolator 3 Nano, built for larger displays and sumps. Explore more reef and marine gear to round out your system.

How it works

The magnet-mounted optical sensor reads your water level to within 0.5mm. When evaporation drops the level, the controller runs the metering pump to add reverse-osmosis water from your reservoir until the set point is restored. Built-in safety logic caps how long the pump can run, so a stuck sensor or an empty reservoir will not overfill the tank or run the pump dry.

What is in the box

• Osmolator 3 optical sensor with magnet holder
• Turbelle high-jet 5000.020 metering pump
• 12V DC power supply
• Tube and tube holder

Features

• Automatic top-off keeps water level and salinity stable
• Optical sensor accurate to 0.5mm
• Quiet Turbelle high-jet metering pump for precise, gentle dosing
• Safety shutoff guards against overfilling and dry running
• Fits aquariums from 5 to 180 gallons
• Delivers up to 6.2m (20.3ft) of head height for tall stands and remote reservoirs

Specifications

Osmolator 3 vs Osmolator 3 Nano

Choose this full-size Osmolator 3 for aquariums up to 180 gallons, sumps, and taller stands. For nano and desktop tanks, the compact Osmolator 3 Nano covers smaller volumes at a lower price.

FAQ

Freshwater or saltwater? Both. It keeps the water level steady on any aquarium, which matters most on reef and marine tanks where evaporation changes salinity.

Do I need a separate reservoir? Yes. The Osmolator pumps from a container of RO or RO/DI water you keep nearby, topping off the tank as it evaporates.

What size tank is it for? Aquariums from 5 to 180 gallons. For smaller nano tanks, see the Osmolator 3 Nano.

Is it hard to set up? No. Mount the sensor with the included magnet holder, set the pump and reservoir, and the controller runs the top-off automatically.