How much heat will a running a Tunze 6000 on controller ad to the water even if it's on a cycle where it's not running full speed all the time? I know they idle them between wave pulses which means they are running all the time, so how much heat do they ad to the water compaired to a large power head that is running all the time? And do they ad less heat while in the idle mode? This is for a 150 gallon tank.