Level-O Auto Top Off — Dual Optical Sensor Overfill Safety for Nano - Reef Casa

The Reef Casa Level-O is an auto top off system built for nano and all-in-one reef tanks. It reads your water level with dual laser optical sensors and replaces evaporated water for you, continuously.

Our advice: an ATO doesn't get installed the night before you leave

Vacation time is not ATO installation time. It has to have been tested while you were home. A system you have never watched run is a system you don't know the behaviour of when you're gone.

An ATO does two things. It keeps your pump from running dry. And it holds your salinity and temperature steady.

Because let's be honest: you cannot top off once a week and expect a stable environment. Between two refills the water evaporates, salinity climbs, and your tank lives on a slope.

Stability is the key to corals that don't merely survive — corals that grow, and hand you colours worth looking at.

What the manufacturer states

• Dual overfill protection via optical sensors
• High precision water level sensor
• Fast installation
• Works with Reef Casa all-in-one models
• Reef Casa bills the Level-O as the world's smallest auto top off system, and states quiet, reliable pump operation

An honest word on noise: it is relative to each person. What goes unnoticed by one owner bothers the next, especially in a living room at night. We report what the manufacturer states; you'll judge it in your own room.

Specifications

• DC pump — max head: 8.2 ft
• DC pump — flow rate: 74 gph
• Sensor cable length: 10 feet
• Pump cable length: 69 inches
• Max tank mounting thickness: 1/2 inch
• Power supply cable length: 67 inches

What's included

• 1 x dual laser optical controller
• 1 x power supply
• 1 x water pump
• 7 ft of water tubing

Check your wall thickness before ordering: the sensor bracket takes up to 1/2 inch. Thicker than that, it won't mount.

What you need alongside it

• The Well 5 Gallon ATO Reservoir — the Level-O needs a freshwater reservoir to draw from. The Well is built to slide inside Reef Casa stands. Sold separately.
• Reef Casa Cube 15 — 15 gallon all-in-one nano reef.
• Reef Casa Nano Cabinet — to hide the reservoir and pump under the tank.

Why buy it at ReefSolution

We are an authorized Reef Casa dealer. Secure shipping anywhere in Canada. Free shipping available depending on your order total.

Frequently asked questions

What does an ATO actually do?

Water evaporates out of your aquarium; the salt stays behind. Without top off, your salinity climbs every single day. An auto top off senses the drop and adds fresh water to compensate, automatically.

Does the Level-O come with a reservoir?

No. The box holds the dual laser optical controller, the power supply, the pump and 7 feet of tubing. The freshwater reservoir sells separately — Reef Casa's The Well, 5 gallons, is built for it.

What is dual overfill protection?

Reef Casa fits two optical sensors instead of one. If the first lets water past, the second kills the pump. It's the single most important safety on an ATO: a system that fails to stop empties your whole reservoir into your tank.

Will it work on a tank that isn't a Reef Casa?

Reef Casa lists it as working with its all-in-one models. The physical constraint to check is the thickness of the wall where the sensor mounts: half an inch maximum.