WD/Sump 1st Chamber - Water over or under?

[aeri]

I've seen several sumps and wet/drys on this site and one thing I've noticed is that most have the water flowing in from the overflow into the first chamber, which then floods and pours into the 2nd chamber, etc.

Whereas some others have the water flowing into the first chamber, but there is a gap on the bottom of the panel where the water pours under into the 2nd chamber.

Is there a right/wrong way? Pro/con? or just preference?

Attached are examples of what I am referring to. Full courtesy to the owner of the pics.

 

[jmotion]

If you do the over method I suggest creating a small lip so it pours over the pad instead of down the side of the baffle. Another setup style is to have the incoming water dump over floss pad and spread across bio balls below via drip tray.

 

[Pharaoh]

The over method is generally for freshwater. The water spills on to the filter media and drip plate. This is the most common IMO.

Most of the under setups I have seen are for saltwater refugiums (sp?). Hence, the protein skimmer. (Although sometimes used int freshwater setups also.)

I vote the over method.