Top-off systems are beneficial to a marine aquarium for a number of reasons. They help keep a constant water level inside your tank resulting in consistent performance from your protein skimmer. They also eliminate the need for daily top offs with fresh water and help maintain steady salinity levels.

The Tunze Osmolator Universal 3155 is one of our best-selling top-off systems. It comes with everything you need in the box so you won't need to purchase additional parts, pumps or accessories before you install it.

The included pump is small and will fit in most top-off containers. It wires with DC voltage for safe operation and easy installation.

The operation of the Tunze top-off system is fairly simple. When the water level drops inside your sump, the optical sensor detects the change and sends a signal to the controller to start the pump and begin filling your aquarium. In the event the optical sensor were to fail and not turn off the pump, a safety float switch shuts off the unit and sounds an alarm.

If you have any questions about the Tunze Osmolator ATO system, please give us a call at 1-800-566-FISH (3474) or leave us a comment below.

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