Which is Quieter in a tank?

[Bluetangclan]

For years I have used the in-tank overflows in my tanks and while they have done the job, they have been louder than I would have liked. Recently I have gotten the bug to take down a grow-out tank for cichlids and start another reef tank and figured I would do something different this time that wouldnt take up so much space in my tank. Which would be quieter to have an external overflow, by cutting the glass in the back and installing a screened bulkhead? or to continue to use the internal overflow? Thanks

 

[rdmpe]

I think the internal overflows give you more options to do a durso or to do a completely submerged drain pipe if you can, similar to this setup http://www.reefcentral.com/forums/showthread.php?s=&threadid=344892 which I use. It is completey silent except for the slight tinkling sound of water falling over the wall of the internal overflow.

It seems to me that a screened bulkhead would not skim the tank surface very well, which is what you want since that is where the wastes tend to end up from what Iv'e read. Or would your screened bulkhead be behind an overflow wall? Also if you aren't skimming off the water surface well enough, you might end up with a layer of stuff on the surface that cuts down on light, gas exchange, etc. Last thing - seems like a screened bulkhead might end up sounding like a toilet flushing as far as sucking air into the drain.