What do you mean by "if the water level is right"? do u mean it has to be at a certain level in order for the impeller to be quiet? or just so the trickling is hidden? or both thanks
Not the impeller the water falling back into the tank.
Quiet Spring - Water falls less than one foot onto next rock
Whitewater Rapids - Water is falling several feet at a high speed; Paddling guide is cussing at you and saying you are going to die if you don't paddle harder