I just got mine all plumbed up, and have fresh water running through it for a test, so far so good. I cut the main drain pipe inside the box at 2 1/2", secondary at 3 1/2", and emergency pipe at 6". I am running about 700-800 gph through it, and it is silent. I did use the U tubes that came with it. The ball valve that I installed on the main drain pipe going into my sump is very useful to adjust the flow, and get it running properly. My bulkheads are less than half way submerged. The holes on top of the U tubes are important, I was told, to get a proper siphon. Your main drain should be almost a complete siphon, and the secondary should just be a "trickle". This is what I was told by a local reef store where I purchased it..and the overflow is working as intended. I cannot speak to the salt creep, as I have not had it running long enough . Hope this helps