Biowheel? Are you using it just to move water, or with a filter pack? They're not really made for saltwater anyway. I'd ditch it, IMO.
Anyway, what noise is it making? Gurgling? or just splashing into the tank? In my freshwater years ago, if my water level went down too much from evaporation, it would make more noise. But the noise would go away once I raised the water levl.