I really was not clear in my question, after re-reading further... In the overflow box, there is no noise at all. Am using a silencer, and the water going down is almost silent. But, the 1" hose carrying the water from the overflow box to the sump does not fill with water, so you get the gurgling noise as the hose enters the sump. You see the air/water mix right at the point of entry. Should I be using smaller diameter hose?
Thanks!