Overflow Return bubble help

[Fragmented 99]

Using a Durso overflow and it works great and have an issue I thought someone may be able to help with.

I have a 120 with a 6" X 6" overflow with a return of aprox. 600GPH through a 1 1/2" drain.
The return is slightly under the water level in the sump but I am getting a large amount of air into the return water which is creating some noise. Any way to eliminate this?

Thanks
Tony:(

[MIKE NY]

Tony.... tie a filter sock on to the end of the pipe and it will trap detris as well as collect the micro bubbles, but it will have to be replaced and cleaned every couple of days depending on your water quality...HTH

[pecan2phat]

Principle of an Durso is to mix air into the water drain so that the level in the overflow box does not siphon and act like a toilet flushing.
So air is purposely mixed in which would create a good amount of bubbles at the exit.
Ideally, the drain should be slightly above the water surface in your sump thus providing for some of the air to dissapate while hitting the water surface but this also creates noise and salt creep. Using a micron filter sock and the exit above the sump ater surface would be the best solution.

[swannking]

Your 1 1/2" drain can handle close to 1200 gph of flow. That's why it is sucking in a lot of air. If you have a ball valve, you can try to close it up a little bit but make sure you still have bubbles going into the sump.

[stando76]

I have the same problem. In order for me to keep up with my pump, I have 2 X 1" U tubes. But the result is the toilet flush sound effect. I have tried to silence this but it just dosent work without affecting the amount of water I am pulling in.