Understanding Heater Failure Modes
Heaters are the most common piece of aquarium equipment to fail. They typically fail in two ways:
- Stuck OFF: The tank slowly cools down. Most tropical fish can tolerate a slow cool down for a day or two until you replace the heater.
- Stuck ON: The heater never shuts off. A single high-wattage heater will cook your tank in hours. Two smaller heaters (redundancy) give you vastly more time to catch the error.