What's a sump?

[Northern]

Hi.
This is going to be an extremely amateur question but I'm still learning
Anyway, what's a sump? I keep seeing people speaking of it and google images return something that looks like a smaller tank that is divided into 3 sections.
What is it? Do I need it?

[slapshot16]

A sump is a separate tank or container. Water from your tank drains into the sump. A pump in the sump returns the water to the tank. A sump increases water volume and gives you a place to hide your heater, protein skimmer and other equipment. Some people add dividers like you described and one chamber is for the water coming in, the second is the return area for your return pump, and the third is for a refugium. A refugium is a place to grow large algea, keep sand and live rock.

You do not "need" it, but it is an excellent nice to have if for no other reason than to have less equipment showing in your display tank.

[NirvanaFan]

Sumps are not necessary, but can be very helpful. They increase the total volume of water in your system. This makes swings in pH, calcium, alkalinity, and other things slower. The more water, the more stable a system is.

It is also a place to store equipment. Typically people store heaters, protein skimmers, and other equipment in sumps. This keeps them out of the display, so it looks nicer. A sump is a great place to keep macroalgae as well. A clip on light can be used and as the macroalgae grows, it consumes nitrates and phosphates from the water.

A sump is a great place to dump alkalinity and calcium supplements as well. This gives them time to spread out in the water and they won't get pushed directly into a coral like dumping them in the display may.

[Northern]

oh, alright then
Thanks

[NirvanaFan]

check this out...

http://www.melevsreef.com/what_sump.html