Eheim Jager TruTemp Submersible Heater - 300 W

As you know, fish from tropical and sub-tropical waters require a constant water temperature. Before the engineer Eugen Jäger invented the aquarium adjustable heater some decades ago, there wasn’t any really satisfactory solution for controlling the water temperature suitably for specific species. People resorted to complicated and sometimes odd methods. Some put the aquarium in the sun or next to a radiator or an oven.

The EHEIM aquarium heater is a further development of the legendary heating rod. 

The temperature can be precisely set from 18 to 34 °C and if required recalibrated (±2°). The temperature control accuracy is ± 0,5 °C. 

The heat is kept at a constant level. The heating function is indicated by a control lamp

The rod is absolutely watertight, can be fully submersed, has an automatic dry run shut-off (Thermo Safety Control) and is suitable for fresh and salt water. 
 
One of the most important innovations is the glass jacket:

• It increases the heating surface,

• condenses the heat, ensures optimum even heat emission and

• forms a heat shield (touching it doesn’t harm the livestock).

The jacket is made from special laboratory glass, which was developed for research purposes. Therefore it is free from pollutants that could be released into the water. It is resistant to chemical and biological substances. It doesn’t have any fissures and hair cracks through which condensation could penetrate. And even extreme fluctuations of temperature that can occur during a water change do not harm this glass.