I have the Aquascene 2 gallon tank. I am currently heating it with the Hagen Radiant heater. I have no idea how powerfull it is but it is pretty big. I didn't buy it, I have had it from previous fish tanks. But it is horrible for small tanks, I will either come home and the tank is like 85-90 or it stays at like 70 and when I try to just bump up the temp a few degrees it will shoot up to 85. I feel so horrible doing this to my beautiful crowntail. What heaters are good for 2 gallons? And possibly are submersible? Thanks!