Eheim Jager 100W Submersible Aquarium Heater

The Eheim Jager 100W Submersible Aquarium Heater hits the sweet spot for many popular tank sizes, comfortably warming aquariums in the 26–40 gallon range. German-engineered precision, a calibratable TruTemp dial, and shatterproof glass make it a set-and-forget favorite — fully submersible for freshwater or saltwater.

Why aquarists trust the Jager

• 100 watts of reliable heat: Ideal for aquariums around 26–40 gallons
• Precise TruTemp dial: Adjustable from 65–93°F (18–34°C) with a calibratable dial for spot-on accuracy
• Fully submersible: Mount it horizontally or vertically, freshwater or saltwater
• Shatterproof glass: Lab-grade, durable construction
• Thermo Safety Control: Automatic shutoff protects against accidental dry running

Setup & safety tips

• Place the heater near good water flow (by a filter outlet) so heat spreads evenly.
• After plugging in or before unplugging, wait ~15 minutes for the glass to adjust to water temperature.
• Always verify the actual tank temperature with a separate thermometer.

Not sure on sizing? Bigger tank? Look at the 125W or 150W. Smaller? The 75W has you covered. Browse all aquarium heaters or the full Eheim equipment lineup.

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