Quite Overflows...

[roscozman]

Here is one I was reading over on RC.
http://reefcentral.com/forums/showthread.php?t=1310585

I use this type of overflow/drain on my fuge. It works well and is dead silent.

I have heard of putting an elbow on one of the overflows to make it a tad higher than the other and placing a gate valve on the lower one. Then tune the gate valve to get a "true" syphon.

Has anyone done this?

On RC, I read the term "Herbie Overflow". That is where they turn a standard RR tank with two hole (1 return, 1 drain) into a 2 drain system and use a hang-on return. If you have two overflows, you just repeat the process.

The overflow rockmp mentions still works for a two pipe drain system. The third pipe is only for back up.