71 Liter Tank With 300 Watt Heater?

[Bigpig]

would a larger watt one not fluxuate the water temperature.

big bursts of heat instead of a slower steady temperature rise.

 

[arobinson1984]

Yes bigpig, you are correct.

A higher watt heater does cause fluctuations in water temperature, whether or not it is enough to have an ill effect on the fish will highly depend on what fish are kept in the tank.

Andy