Product Size of Aquarium Power Consumption Tetra HT 25 10 - 25 l 25 watt Tetra HT 50 25 - 60 l 50 watt Tetra HT 75 60 - 100 l 75 watt Tetra HT 100 100 - 150 l 100 watt Tetra HT 150 150 - 225 l 150 watt Tetra HT 200 225 - 300 l 200 watt Tetra HT 300 300 - 450 l 300 watt