Discount Leisure Products\nEHEIM Thermocontrol Aquarium Heaters - 3 year Eheim guarantee\n\nSizes from 25 watts to 300 watts available\n25w - 243mm - Tank 20-25 litre50w - 243mm - Tank 25-60 litre75w - 270mm - Tank 60-100 litre100w - 319mm - Tank 100-150 litre125w - 319mm - Tank 150-200 litre150w - 345mm - Tank 200-300 litre200w - 406mm - Tank 300-400 litre250w - 452mm - Tank 400-600 litre300w - 506mm - Tank 600-1000 litres\n\nObvious ideas often are the best ones. For example, the aquarium heat-er as a rod. The heating rod is simply hung in the water and heats it. It is true that the principle is still the same as decades ago. But a lot has changed in the meantime. And today the EHEIM adjustable heater is an ultra-modern electronic thermal device with the best available tech-nology. A jacket made from special laboratory glass increases the heating surface, serves as a heat shield and ensures optimum even heat emission. And no matter if you want to heat a 20 or a 1000 litre aquarium .