Okay now Im following you Jim. The durso used to enter some flex line then would droop down and the come back up into the sump. Now it just goes straight in......too much flow too fast.
Now correct me if I am wrong here, but I need to restrict the air and or slow things down right?
Oddly I just removed the 90 at the top of the Durson so now its just a straight stand pipe. The gurgle went away put now it just sounds like a loud drain.