Reliable warmth for your aquarium The Eheim AEH3617090 200-watt Jager heater is engineered to maintain steady, safe temperatures in freshwater and tropical tanks

At 16 inches long, it blends into most canopies and tanks without protruding, while delivering consistent heat across the water column

Calibrated for accuracy One of the standout features is a built‑in calibration function that helps you dial in the exact temperature

You'll want to validate the heater's setting with a reliable thermometer, and calibrate using the quick method described below

In-tank calibration is possible, letting you fine‑tune while the heater runs A 5-gallon bucket setup makes quick, controlled adjustments in a smaller volume The red indicator arrow provides a visual cue to match the thermometer reading How to calibrate (quick guide) Place the heater in a bucket or tank and set the target temperature Immerse a dependable thermometer and wait for the water to stabilize If readings differ, rotate the red adjustment arrow until the water matches the set temperature Return the heater to your aquarium and monitor for stability over the next 24–48 hours Durability and craftsmanship Made with German engineering heritage in mind, the Jager heater emphasizes reliability and long-term performance

It’s built to withstand routine aquarium maintenance and regular water changes, with calibration controls designed to minimize drift over time

What you’ll notice in use Imagine a stable, comfortable environment for your fish and plants, with less temperature fluctuation between day and night

The heater’s 200 watts are designed for medium to larger tanks, helping you avoid abrupt temperature swings while you feed, clean, or observe your aquatic life

What’s included Jager heater unit (16 inches, 200 W) Calibration instructions and support Mounting hardware for typical aquarium setups FAQ Q: What is the calibration feature on the Eheim Jager AEH3617090

A: The heater includes a built‑in calibration function to adjust temperature to match a thermometer reading, reducing deviation

Q: How should I calibrate the heater before using it

A: Calibrate in a small bucket (5 gallons ) with a thermometer; adjust the red arrow until the water matches the set temperature