Annoying rushing sound from overflow box

[Idech]

The overflow box is making this constant rushing sound, like the sound of wind passing through. I sit in front of the tank most of the day and it’s really annoying. The sound is coming from the left side (secondary drain).

My return pump is set to about 750 GPH (about 5.5 turnover/h), so I don’t think it’s too fast. At lower speed it’s not making as much noise but I would rather not turn it down.

Water in the overflox box sits right at the top of the secondary and emergency drain. That’s how it is most quiet.

Besides that wind sound, it’s really quiet as long as the gate valve is correctly set. Very minimal water sound.

Any tips to correct or at least improve it ?

Thanks !

 

[Reefering1]

You can remove the coupler on end of pipe and put a T or 90* fitting on.. should make it quieter

 

[Idech]

You can remove the coupler on end of pipe and put a T or 90* fitting on.. should make it quieter

There is nothing on the end of the pipe. It can’t be seen on the picture because of the angle.

 

[Reefering1]

Better pic?

 

[Idech]

Better pic?

Left side

Slightly different angle.