i got a 3 gallon tank im gona use for a betta girl here soon , i got one of those betta bowl heaters and it made the tank too hot. so i exchanged it for a marine land 10 W heater for up to 3 galllons, says its pre set for 78 but my tanks at like 82 now?? is that to high for a one lone betta? plz help i need to get a good heater for such a small tank ,,,,>>>>???????