Ok, so I wanted to see if anyone might have a suggestion on how to quiet this overflow down a little more. Here are some pictures of what I have, an original Ghost Overflow not the new injection molded one that doesn't use bulkheads. I didn't notice until I had already plumbed the thing, that the emergency drain should have been in the center. That is the secondary drain in the middle. I plumbed them in the order they enter the sump. I made my own 1" U-Tube out of two 90° elbows that I cut down. No way a second one will fit in that middle slot, so the secondary and emergency drains are just straight pipes.
I don't believe any of the sounds I am hearing are from the siphon. The water level in the external box is running just below the secondary drain and very little, if any, water goes down that pipe or the emergency pipe, so not from them either. I think it is the water coming from the internal box through the two bulkheads. Am I running the water level inside the box too low? I have both of the Vectras running at about 30% and the siphon seems to be handling all of that well. No air is going in the sump. (Sorry for the mess on the floor behind the tank. It is a construction zone.
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Water level at the secondary drain in the middle. It stays about ½" below the top of the pipe.
Water level inside of the box at the emergency drain. It stays about 1" below the top of the pipe.
The top of the U-pipe on the siphon. I have a John Guest fitting to purge any air at startup. It stays closed.
Water level at the bulkheads coming from the inner box. My next step was going to be to cut some more (longer) pipes for the secondary and emergency drains and raise the water level further up in the outer box.
Also thought about raising the water level inside the sump. There is a little noise here from turbulence. I could turn down the Vectras I suppose. The water level in the sump is at about 7" right now.
I have a 45° fitting on the end of the siphon. No noticeable air is coming down the siphon. Virtually no water coming out of the secondary drain.
As I mentioned, I have never had one of these overflows, so if anyone sees any noticeable bonehead mistakes, please speak up. TIA