With the EHEIM precision heater your fish receive exactly the right temperature – in any aquarium.

The EHEIM Thermocontrol 200 W is an adjustable, electronic aquarium heater (“rod”-type) designed for medium-large aquaria. It gives users full control over the target water temperature, includes safety features, and uses high quality materials. It’s suited for tanks around 300-400 litres where stable and accurate heating is important.

Key Features 

• Adjustable Temperature Range: You can set the heater between 18 °C and 34 °C.

• Precise Control: Regulation accuracy around ± 0.5 °C ensures you reach and maintain the desired temperature with minimal fluctuations.

• Recalibration Option: It allows safe recalibration of the thermostat by about ± 2 °C in case the default setting needs fine-tuning.

• Indicator Light: A control lamp shows whether the heater is actively heating (often red) or when the set temperature is reached (often green).

• Full Submersion & Waterproofing: The heater is designed to be fully submerged and is waterproof.

• Dry-Run Protection (Thermo Safety Control): Protects the heater (and tank inhabitants) from damage in case the water level drops or the heater is not properly submerged.

• Glass Jacket: The heater is encased in special laboratory-grade glass which:

  • increases heating surface,

  • helps distribute heat evenly,

  • acts as a heat shield (so touching the glass is safer for aquarium life), and

  • is resistant to chemical/biological effects and temperature fluctuations.

• Physical Build / Install Features:

  • Cable length of about 170 cm for flexible positioning.

  • Includes double suction-cup holder for secure mounting.

• Compatibility: Suitable for both freshwater and marine (saltwater) aquariums.

• Warranty & Origin: Backed by a 3-year manufacturer’s warranty. Made in Germany.

Technical Specifications

• Power: 200 Watts at standard mains (50 Hz).

• Recommended Aquarium Volume: Roughly 300 to 400 litres.

• Height / Length: Approx 406 mm.

• Diameter: About 36 mm.

Advantages of using EHEIM thermocontrol 200 W

• Provides good power for medium-large tanks, capable of maintaining stable temperature even when ambient room temperature varies.

• The adjustable setting (18-34 °C) gives you flexibility for different species or seasonal adjustments.

• Accuracy (±0.5 °C) and recalibration ensure you can fine tune heat delivery.

• Safety features (dry-run protection, waterproof design) help avoid risks of overheating or failure.

• The glass jacket gives better heat dispersion and is safer to touch than unshielded heaters.

• Good mounting and cable options help you place it well to optimise heating distribution.

Limitations 

• Its physical size is significant (≈ 40.6 cm length, 36 mm diameter), so it will be visually noticeable in smaller tanks and requires space.

• While the heater can raise temperature, it cannot cool. If the aquarium gets too hot (e.g. in a hot room), you’ll need additional cooling solutions.

• The heater needs to be fully submerged according to specifications; improper submersion or water level changes could trigger safety shut-offs or risk device stress.

• Because precision and build quality are high, cost is higher than simpler fixed/preset heaters.

• In colder environments or poorly insulated tanks, even 200 W may struggle to maintain higher set temperatures unless your ambient conditions are favorable.

The EHEIM Thermocontrol 100 W is a high-quality, adjustable aquarium heater ideal for small to medium tanks (around 100–150 L). It offers temperature control from 18 °C to 34 °C with about ±0.5 °C precision, and features a laboratory glass jacket for even heat distribution and added safety. It includes dry-run protection, submersible construction, an indicator light, and a long cable with suction cup mounting. Backed by a 3-year warranty, it’s a reliable choice for stable, customizable heating in freshwater or marine setups.