Sump and Refugiums
Quite simply, the sump is often the heart of the whole system.
They give us an extra space to put any life supporting machinery mechanical filtration, skimmer, media reactors, heater, dosing pump lines or a refugium to harbour another world of life out of the way and provide some extra water volume to the system.
In turn, the extra volume helps a little bit with the aquariums stability in water chemistry and temperature.
This is a "refuge" area, it typically has some live rock, various types of macro algae (desirable species) and a light in the 6500k spectrum (freshwater plant grow light) this creates a small ecosystem separate to the main display in which small creatures can thrive.
These small creatures usually make their way to the display tank via the return pump and become food for corals and fish.
The macro algae uses up undesirable nutrients in the water as it grows and you harvest the excess algae to permanently remove those nutrients.
A well made and maintained refugium is an excellent addition to any reef aquarium.
Glass divisions known as "baffles" are set in place to create each compartment.
A bubble trap is a series of 3 or 4 closely spaced baffles placed right before the return pump.
They direct water over and under them, each time the water is pushed up the micro bubbles created by machines such as the skimmer are left at the surface where they cannot be pulled into the return pump.
There is no huge danger of having these bubbles but they cause the aquarium display to look dirty and they burst on the surface creating salt spray on your lights ect.
Simply just a container with an inlet and outlet for low pressure water to flow over or through various types of media.
Usually plumbed in with a small valve to adjust the pressure to the perfect level.
You can use as many as you like or none at all. Absorption medias such as granular ferric oxide (GFO) or bio pellets for nutrient reduction are usually used in them.
THINGS TO CONSIDER.
Information provided by:MARINE AQUARIUM FANATICS AUSTRALIA