Aquarium Heater with Thermostat 25 W, 18.5 cm — sera SE-08700

The sera Aquarium Heater with Thermostat 25 W, 18.5 cm is a compact immersion heater designed to maintain a stable water temperature in small freshwater and tropical aquariums. Its 25 W output and 18.5 cm length make it suitable for low-volume tanks, breeding setups and hobbyist aquaria that require gentle, continuous heating. The integrated thermostat automatically regulates the temperature within a narrow range to reduce fluctuations and support fish health and biological processes.

Advantages

This aquarium heater combines a low power rating with a built-in thermostat to provide energy-efficient, automatic temperature control. The compact glass/tube construction allows for unobtrusive placement inside the tank and simple installation. Robust materials offer corrosion resistance in freshwater use, while the concise design reduces the risk of obstructing decorations or filtration flow. The device is intended for continuous operation, delivering steady warmth appropriate for small tanks and specialized setups.

Suitable for

• Small tropical freshwater aquariums
• Breeding tanks and fry rearing
• Planted nano aquaria requiring gentle heating
• Desktop or office aquariums with limited volume

Key specifications

• Power output: 25 W
• Length: 18.5 cm
• Integrated adjustable thermostat for automatic temperature regulation
• Glass or tube-style compact construction for internal placement
• Designed for continuous low-power operation

How to use

Mount the heater vertically or according to the manufacturer’s instructions inside the aquarium, fully submerged and placed away from direct contact with gravel or decorations. Set the thermostat to the desired temperature appropriate for the stocked species, then allow the heater to reach equilibrium while monitoring the water temperature with an accurate aquarium thermometer. Verify stable operation for several hours before leaving the aquarium unattended and make minor adjustments to the thermostat if needed to achieve the target temperature.

Usage recommendations

Position the heater where there is good water circulation to ensure even temperature distribution. Regularly check the external thermometer and inspect the heater for damage or deposits. For tanks with larger volume or significant heat loss, consider a higher wattage model or additional heating elements to maintain consistent temperatures.