Another Overflow Noise Thread

[Mole]

Ok, so I have my 65 gallon reef ready up and running. It's still cycling and I'm trying to tune the overflow to be quieter. It came with a durso overflow which is about 1 1/2" in diameter which goes through a 1" bulkhead. I plumbed from the bulkhead to the sump using 1" sch40 pvc. I'm running a mag 9.5 through 3/4" shc40 pvc through the 3/4" return bulkhead and split to two 1/2" loc lines. I did the math for the rise of the plumbing and I should wind uf with about 350gph of flow at head height of 4' (turnover rate of 5.38 times/ hr). I've tried both the durso that came with it and a "hofer" gurgle buster (worked great on my external overflow).

My problem is, when I have the return valve full open and the overflow valve full open, it seems that the overflow fills and then dumps creating a tremendous amount of turbulence and noise in the sump (think capping one end of a tube, filling it with water then immediately removing the cap. If I open the overflow valve and close the return until it stops dumping the water in the overflow (read as returning water to the tank at the same rate of speed with which it flow out) then the constant running water noise of the water going into the overflow drives me crazy. Am I just not there yet and I need to close both valves better so they mesh? Do I need to go with bigger overflow tubing from the bulkhead? Or am I missing something altogether?

Help me out here please.

 

[Jimbo662]

how far below the water line does the drain line go into the sump?

 

[Mole]

exit of overflow dump sits 1" below the water line in the sump

 

[Jimbo662]

Can you post pics of your plumbing?

 

[Bad Company]

To have a completely silent drain, you need two drain lines. One that operates at a full siphon and is tuned with a gate valve to keep the water level in your overflow just below the teeth. The second drain is oversized and is for emergency puposes, it sits at a level slightly above the bottom of the overflow teeth opening, and only carries water if the other one plugs up.

This makes the system safe and silent.