heating my 120gal tank

[Mgamer20o0]

i bought a 120 gal tank and it didnt have a heater. i wanted to know what to get. how many watts per gal. also would it be better to get two smaller ones for each side than one big one?

 

[famman]

I think I'd go with a 300 watt on each side. That way if one fails, the other can hold the tank. You could also put one in the tank and one in a sump.
good luck