Where to Place a Heater for Even Temperature
Same heater, same wattage, same dial setting: move it twenty centimetres and a long tank can lose most of its gradient.
Same heater, same wattage, same dial setting: move it twenty centimetres and a long tank can lose most of its gradient.
Heaters rarely die without warning, and the earliest warning is a swing that widens while the average temperature still looks fine.
Before you move the dial, prove the error is real, measure it across a full cycle, then correct by the offset.
One of these can be corrected when it reads wrong and raised when a fish gets sick, and the other simply cannot.
Room temperature, not tank volume, decides how many watts you actually need, and the old per gallon rule gets it badly wrong.