I'm setting up a nano tank and I need a heater suggestion. I'm a little low on funds so I'd like to find a relatively inexpensive heater that I can trust to keep my tank at around 80 degrees. The tank is for a betta and possibly a couple of ghost shrimp. The heater I have now is really unreliable. The temperature is swinging back and forth from 68 to 84 degrees. It got up to 90 at one point before I unplugged it. I don't want to kill my fish.
I should probably mention that the tank is 2.5 gallons but with substrate is really about 2 gallons of water.