How to quiet the overflow

[LunaSky]

My 90 gallon tank is drilled at the bottom with a stack overflow box. Its a Peter's Aquaverse reef tank if that helps. It does have a turn valve to open or close the flow through the pipes, plus an emergancy pipe. I have a Jebao EP 3500 return pump and no matter the power level (30-100) the overflow box sounds like a river. Not like air is trapped, but more like a sink drain... only louder. Im wondering if someone has any suggestions on how to make it quieter.

 

[KrisReef]

Got a picture?

A general guess is that I would add a standpipe to each drain hole so that the water doesn’t plunge from the overflow surface into a long waterfall to the bottom of the tank in the overflow section.hth?

 

[Shirak]

If there is an emergency drain then you should look up how to tune a Herbie type two tube drain system. I like to have the main drain pipe fairly short then let the water level rise up far enough above the top so you have a full syphon going without any air getting sucked down. The emergency drain should be above that water level. Some like to set the water level so a tiny trickle goes over the emergency drain. Just be careful that the emergency drain is always wide open and never blocked or you risk a tank overflow.... The outlet for the emergency drain should also not be down in the water in the sump IMO or it could get air locked and not flow properly if it needs too.

 

[mfinn]

Looks like you have a pump that does 924 at zero head.
On a 90 gallon tank I would shot for about 5x turn over through the sump( 450 gph).
To start off with I would set the pump at about 75% power. You can change this later if you want.
Assuming the drain line is 3-4 inches lower than the emergency drain line I would slowly close the valve until the water level goes up to the top of the emergency drain line and goes in. Then very slowly turn the valve open, just a tiny bit at a time until the water level drops just below the lip of the emergency drain line.
Hopefully the valve is a gate valve and not a ball valve. If it's a ball valve I would change it out. I've never had any consistent luck trying to do this with a ball valve.
This whole process could take a while until you get the feel of making these adjustments.