The Osmolator 3 3154 is a high-end water level controller designed for both freshwater and saltwater aquariums. Its job is to maintain a constant water level (to compensate for evaporation), thereby stabilizing salinity in marine systems and reducing water line fluctuations in freshwater tanks.

Unlike simpler ATO devices, it features built-in redundancy and safety mechanisms (optical sensor + thermal safety sensor) to avoid overfilling.

It is a “plug & play” system: all necessary hardware is included (pump, tubing, sensor, mounts), so no additional software configuration is required.

Specifications

• Primary optical sensor detects the water level with 0.5 mm accuracy.

• Independent thermal safety sensor stops the pump if the primary sensor fails, preventing overfill.

• Suitable for aquarium glass thickness up to 15 mm (0.59 in).

• Tube holder accommodates tubing up to 22 mm (0.87 in) diameter.

• Comes with a Turbelle® High Jet 5030 dosing pump with dry-run and blockage protection.

• Pump can deliver water up to 6.2 m (≈ 20.3 ft) head height.

• Two selectable pump performance levels (standard and boost).

• Ten-minute safety timer stops pumping if the water level is not reached (protects against leaks or sensor faults).

• Minimum dosing time of 10 seconds prevents rapid on/off cycling.

• Venting/priming routine pulses the pump for ~10 seconds at startup to purge air from the line.

• Automatic restart after dry-run or blockage (system periodically retries operation).

• High-quality, saltwater-resistant cables designed to remain flexible and durable.

• Low-voltage 12 V DC power supply (meets medical safety standards).

• Operating temperature range 15 °C to 35 °C.

• Comes as a complete plug & play kit: magnet holder, tube holder, tubing, hose connector, sensor, and pump all included.

• Made in Germany with emphasis on durability and reliability.

• Backed by a 5-year manufacturer’s warranty.

Additional Details for Osmolator 3 3154

• Because it has a dual-sensor approach (optical + thermal safety), the Osmolator 3 3154 is safer than many simpler single-sensor ATOs—there is a backup measure if the primary fails.

• To switch between the two pump performance levels (standard vs boost), the manual states that you disconnect and reconnect the power multiple times within 5 seconds; after three reconnections, the LED blinks fast to indicate that boost mode is active.

• In boost mode, the pump in this ATO can deliver 112 L/h at a head of 1.2 m. In standard mode, the flow is lower (suitable for quieter operation) and better for many typical setups.

• It includes a venting / priming routine during startup, where the pump pulses for ~10 seconds to purge air from the line. This helps reduce issues with air in tubing.

• The safety timer (10 minutes) is a last line of defense: if after 10 minutes the water level is not achieved, the pump is forcibly shut off, avoiding overfilling due to a sensor or hose issue.

• If the pump is idle (no water supply) and dry-run protection triggers, it will try again periodically. This is beneficial because sometimes air bubbles or temporary flow interruptions can cause false dry-run, and the automatic retry prevents the system from permanently shutting down.

Installation Tips

• Choose a stable location for the sensor
  Mount the optical sensor in an area of your sump or tank where the water level is relatively calm — away from return pumps, skimmers, or splashing. This prevents false triggers.

• Use the magnetic holder properly
  Clean the glass before attaching the sensor’s magnet to ensure a tight, bubble-free fit. The holder is rated for up to 15 mm glass thickness; do not exceed this or the magnet may slip.

• Position the thermal safety sensor slightly higher
  This backup sensor should sit just above the optical sensor’s waterline. That way it acts as an emergency stop only if the water rises too high.

• Keep sensors free from deposits
  Wipe the optical and thermal sensors periodically with a soft cloth or sponge to remove salt creep, biofilm, or lime deposits that could impair their accuracy.

• Secure the outlet tube correctly
  Use the supplied tube holder to clamp the hose above the maximum waterline. This prevents siphoning or backflow from the aquarium into your reservoir.

• Avoid kinks in the tubing
  Route the tubing smoothly with gentle curves so the pump can deliver water without restriction.

• Prime the pump after installation
  When first powering up, the Osmolator automatically runs a venting routine (short pulses) to clear air from the line. Let it complete before relying on normal operation.

• Set up the reservoir close and below the aquarium
  Ideally the pump draws from a reservoir located below or beside the tank. If the reservoir is too high, there’s a risk of gravity siphon; if too low, check the pump’s head height rating (6.2 m max).

• Check the safety timer duration
  Make sure the 10-minute maximum dosing timer suits your evaporation rate; adjust reservoir size or evaporation control if necessary.

• Test the system
  After installation, manually lower the water level to trigger a fill and observe how the system behaves. Also simulate an overfill to see the safety sensor cut the pump. This helps you understand its operation and confirms everything is working.

• Keep the power supply dry
  Mount the 12 V DC power supply in a dry, splash-free location outside the stand or above sump level.

• Regularly inspect the pump
  Every few months, remove and rinse the Turbelle® High Jet pump to clear any debris or buildup. This preserves flow rate and reduces noise.