controlling air "bubbles" from Durso standpipes

[hqgc]

I have two 1.5 " supplys to my sump that are dursoed from my tank. The amount of air that enters my sump from my standpipes is quite large.
My question is
1. Is there anyway to control the air intake into the standpipes without causing problems inside the overflow.
Right now the the water level is just above the halfway mark of the street ell 90 elbow in the overflow.

[Pescador]

It sounds like you have the air adjusted at the right level if it's stays steady halfway up the elbow. If you restrict the air it's going to rise and fall and sound like a toilet flushing.
How far is the water falling in the overflow? Maybe you can raise the level with a longer standtube might that might help a little.
I use two 7" filterbags on my two returns from a 2" Durso and they totally eliminate any bubbles in the sump.

[untamed]

1) Are both 1.5" drains in the same overflow box?..or do you have 2 overflow boxes, each with a single 1.5" drain?

2) If you have 2 drains in 1 overflow, that's good..find out if 1 of those drains can handle the entire flow. Temporarily remove one durso to find out if a single drain can take the whole flow.

If one drain can handle the entire flow, then you are home free! There is a perfect solution for you that will silence your system completely. It's called the "silent siphon", or the "Herbie Method".

If a single drain can't quite keep up with the entire flow, you can still do it with a dramatic reduction in bubbles and sound, but it won't be completely silent.

If you need both drains running nearly full in order to keep up with the flow, then you are stuck with dursos and the other recommendations.

[hqgc]

2 overflow boxes each with a durso. Any ideas?

[untamed]

2 overflow boxes each with a durso. Any ideas?

Not the best for my solution. You'll need to modify in order to do what I have in mind.

1) Is there room in each overflow to add another drain? Even a 1" might make the entire difference.

2) Can you make a 1.5" connection BETWEEN the two overflow boxes? Even though water would cascade into separate boxes, they would behave like a single box. If this connection pipe was also a drain, you would have created a single box with 3 drains.

Are your overflows glass? If so, drilling them out for another connection might be too difficult. If you can't do either of the above, then my idea would be too risky to run with.

[hqgc]

Are your overflows glass? If so, drilling them out for another connection might be too difficult. If you can't do either of the above, then my idea would be too risky to run with.

The overflows are glass. And the tank is running.