The Tunze Metering Pump 5000.020 is the official, manufacturer-specified replacement pump for the highly popular Tunze Osmolator and Osmolator Nano auto-top-off systems. This low-voltage pump is designed to reliably deliver fresh water from your reservoir to your aquarium, precisely replenishing evaporated water and maintaining stable salinity, a critical factor for a healthy reef environment. It serves as a direct replacement part, ensuring seamless integration and restoring your ATO's original functionality.

Engineered for quiet and consistent performance, this compact metering pump operates on a safe 9-volt DC power supply. It offers impressive flow rates for its size, delivering 13.74 gallons per hour at a head height of 2.95 feet and 7.13 gallons per hour at 6.56 feet. With a maximum head height of 7.22 feet, it is capable of handling most aquarium and reservoir setups, easily pumping water from a container on the floor up into your sump or display tank.

This replacement pump is an essential component for any aquarist currently using a Tunze Osmolator whose original pump has worn out or failed. Rather than replacing the entire auto-top-off unit, this part provides a cost-effective solution to get your system back online quickly. It is ideal for hobbyists who depend on the reliability of their Tunze ATO for maintaining a stable and thriving saltwater aquarium, preventing dangerous salinity swings.