This high quality heater can be placed fairly low in the water.  The submersible heater has an internal thermostat, it is usually more efficient if you position it horizontally in the tank, and fairly low in the water column. This will help the thermostat get an accurate reading on the tank temperature and correctly activate and deactivate the heater.

• Submersible heaters are attached with suction cups.
• Optimal water temperature is 18 to 20 Degrees Celsius.
• Compact and reliable quality
• High quality heating element
• Fully submersible
• For marine & fresh water aquariums
• Hydroponics
• Aquaponics
• Easy to set and adjust temperature
• Using the vacuum cups makes it easy to place the heater safe on the inner side of your nutrient tank.
• High accuracy (0.5 deg C)
• Frequency :  50Hz
• voltage        : 240V

50w Unit will service 50L of water