Best way I found to reduce pump noise is to insulate it. In my case I have a DDC style pump, and its very quiet after I got a car wash sponge and cut a square

Best way I found to reduce pump noise is to insulate it. In my case I have a DDC style pump, and its very quiet after I got a car wash sponge and cut a square hole in it and put the pump inside. It looks ghetto but its inside a case so who cares. At first I was worried about heat, but its lasted 10 years so far.