There are many possibilities of setting up a marine aquarium however a basic setup would consist of a display tank, with an overflow running down to a second tank, called a sump. Water then returns via a return pump to the display tank.
This, as the name suggests is the actual display in which the fish and the corals are housed. Flow pumps such as Seios and Tunzes will be placed in here as well.
Water flows over this pane and creates surface skimming, water then goes down standpipes to the sump In the Overflow a Durso standpipe will quieten the gurgling noises from the water flowing down the pipe to the sump
Durso Standpipe - Durso Standpipes
The Sump is a container (generally a second tank) that will hold the unsightly equipment such as the skimmer etc It also houses the Deep Sand Bed.
The Last chamber houses the return pump and the auto top up float switch (if installed) for Topping Up with Reverse Osmosis water.