I run a setup in Florida, what's a heater?
Pretty much dual heaters, or even more, works well. When I started, I ended up experimenting with heaters too much and just went overkill, then I was wasting money. Now I run 2 200W heaters in a system holding about 220 gallons and 2 150W in systems holding less. They are almost never on. But the room is warm.
Now cooling is another cost.
Jeff