I have a submersible pump feeding an upflow filter. It makes an
annoying noise. The pump itself is silent and the sound of the water
flowing into the pond is pleasant. The problem is the sound of the
water flowing out of the filter. It makes a rushing/gurgling sound. The
water leaves the filter through a closet flange in the side of a
barrel. Can anyone offer a tip on how to silence it? It drowns out the
waterfall.

Cam