I would recommend mounting your heater horizontally near the bottom of the tank. U will be able to heat the water and distribute heat more evenly. U can then use live rock to hide the heater.
I would add another power head to the other side of the tank, you don't want any dead spots for detritus to just sit. Is that a glass heater? If it is I highly recommend titanium because you never have to worry about the glass breaking and nuking the tank.