Hi Everyone
just wants to let you know i found the issue and fix it.
size of pipes inside the bubble trap area was the issue.
i cut main one around 2.5 inches below water line and second drain around 5 inches. i still can hear some noise from second drain inside the overflow box and not sure what is that. not sure if i should cut the second pipe same size as main one?
also i appriciate if someone help me to set the water level of aquarium sump filter.