Need some advice, thanks

[Shipwreck]

A sump is primarily a holding tank for extra water, pumps, skimmer, heater, calcium reactors, sensor probes, autotop off and any other equipment that you don't want to see hanging in you main tank.

A fuge or refugium is a place to hold additional liverock, house a deep sand bed and grow macro algae (most common is Cheato). The purpose of this area is to add to the filtration of your system. The additional live rock provides more surface area for the beneficial bacterias to grow, as well as to give an area for pods (copepods, mysis, etc) to grow and breed with no preditors. A deep sand bed (optional) creates an area of low oxegen and denritification will occur. The macro algae is used to export excess nutrients. As the algae grows it takes up the same nutrients that the bad algae's use. You then remove a portion of the macro and dispose of it, thus removing these nutrients from the system.