If you want to upgrade your Fluval Edge Aquarium to a tropical tank, this Fluval Edge 25w Heater is what you need. It is preset to 26 degrees Celsius for easy installation and is perfectly safe and durable.
Please note that the Edge heater will maintain the water temperature within 2-3C of the ambient room temperature. If the room is very cold it may appear that the heater is not working, it is, but may not be able to reach the desired temperature within the tank, (particularly if the light is on).