Quiet durso?

[Stussi613]

My durso's are pretty quiet in my overflow boxes, but they are noisy as hell where they exit into the sump.   I'm using dual 1" durso standpipes that hit two 45's below the bulkhead and then a 90 into the sump chamber where they exit 3" below the water line and gurgle like crazy. I've tried limiting flow on the side with the long plumbing run to the sump (the other basically drains straight down-ish) and I've tried the airline tubing in the hole on top of the cap and no change.

I'm thinking maybe the holes in the caps aren't big enough?   I was going to convert to herbie style and change the returns to over the top since I have room...But if just drilling a bigger hole, or using longer tuning will help I'd rather try that first.

Thoughts?

[Greatwhite]

I've never seen/heard a quiet durso...  Mine was about as quiet as I've come across, but there was still a steady burble of water there.  It drained into a bubble tower, which may have helped.  If you're just draining straight into the sump (below the surface) I would imagine there'd be a lot of bubble action.  The bubble tower keeps the bubbles contained, and all the excess air is released straight up.  The water overflows from the tower into the sump.

From what I understand, Herbie is the quietest overflow, and you don't get all the bubblin' that you get with durso...

[Greatwhite]

Take a look at this picture...  I had a pre-fab Aqueon Proflex sump.  The water enters the bubble tower, comes up and over the flat black surface and out the 2 holes into the sump.  Filter socks go in those holes, which quiets it down ever further.  I stopped using socks, and dealt with the water noise, which really wasn't that bad.

[fischkopp]

Ditto, durso isn't quiet unless the amount of water going down the pipe is minimal. Check out beananimal style overflows. These are virtually silent. All you hear is a humming of the pump you use.

[Stussi613]

I know they probably won't be dead silent, but they were as loud as a washing machine when I started the system to check for leaks and I don't have an enclosed stand.   I'm going to try drilling the holes in the cap bigger to stop them pulling so much air.

[Greatwhite]

I may be waaaay off, buy wouldn't a bigger hole in the top cause it to draw more air?  If it's not "flushing" and raising the water in the overflow up and down, the hole is probably just right...  Maybe you have too much flow from your return pump...