Dream sump

[Eb0la11]

The often three baffles configured together that have water flowing over the first one, under the second one and then again over the third one are collectively known as a bubble trap. This baffle design often follows the skimmer chamber as water exiting a protein skimmer can be extremely aerated and this trap helps the bubbles to collect at the surface resting against the second baffle while clear "airless water" glides peacefully under the surface under the second baffle and then again over the third back to the display tank.

There are some single baffle configurations after a chamber like a refugium where bubbles wouldnt be forming.

Hope that helps.