Marina 25 watt heater for all tanks 25 litres or below Very popular for the fluval edge 26 litre. - The Marina C25 is a 25 watt compact, submersible heater for use in indoor aquariums. - Without any adjustments needed, it is designed to reach and maintain the set temperature of 26ºC (78ºF). - The exterior is made of a tough polymer so that it will not crack or break like traditional glass sleeve heaters. - The heater is ideal for aquariums up to 6.6 gallons (25 L) and can be used in fresh and saltwater tanks. - Includes an LED running lamp and 1 suction cup for easy and secure installation.