When taking powerheads out of the aquarium for long periods of time, make sure to soak them in vinegar prior to putting them back into operation. As pumps operate 24/7 in our saltwater tanks, they accumulate many different growths on the motor, propeller, and housing. As the pump dries out, the crud causes the impeller to either become unbalanced, not run as smoothly, or even seize up. Upon putting the pump back in service, the off balance or seized up propeller will attempt to spin, but it may cause the propeller assembly to break. This will lead to a propeller that constantly makes a clicking noise or doesn’t push any water.