Wavecontroller or No Wavecontroller

Hey, whats the difference between a controllable and non-controllable powerhead? I was wondering if its worth buying a controllable pump. I accidentally purchased a controller before doing the research, now I've got a chance to buy a Tunze 6045 and 6015 for $80.00 second hand, but they aren't controllable.



I want to know if its worth it for me to invest a bit more and get the controllable pumps since I already have the controller or should I just buy the two other pumps and take the controller as a loss.



thanks