Analog heaters have been a popular choice for many years due to their simplicity, reliability, and affordability. Aquatop offers the best selection of heaters ranging from 25W to 400W with a tank capacity up to 100 gallons. Temperature can be set from 68-93F and the heaters are suitable for both fresh and saltwater use. Specific wattages are suitable for gallon amounts up to 13, 20, 25, 40, 50, 65, 75, and 100.