Practical guide
How to choose an aquarium heater
Heater size depends on more than litres; temperature difference and heat loss also matter.
Measure conditions
Check the lowest room temperature, target water temperature and actual net volume. A tank near a window or cold wall may lose more heat.
Consider redundancy
In larger tanks, two smaller heaters can distribute heat more evenly and reduce the impact of a single device failure.
Verify independently
Use a separate thermometer and monitor temperature after changes. The calculator is a starting point, not a replacement for manufacturer instructions.
Important: Adapt actions to the species, equipment instructions and actual measurements. For signs of illness, consult a veterinarian experienced with aquatic animals.