Overflow Box question.

[ChunkyBlenny14]

How do I fine tune my overflow so it's silent? Should I use the white pvc on my main drain or take it out? Thats my main question do i neet it or just go without? Water level to emergency drain is about 1/2 " but isn't consistent. Thank you

 

[Uncle99]

I only use the red, nothing on the right.
Or lower the height of the white one so it stays under water.