[Narmical]

I'm don't really understand the use of sumps. Are they use as a filtration mechinisim? so if you have a sump it is sufficient to handle mechanical and chemical filtration and no other "hang on" thing or "canister" thing is needed?

[Samper]

Many people use a sump to house equipment that doesn't need to be seen like heaters, skimmers, probes and monitors and most incorporate a refugium into it but if possible I'd go with a gravity fed fuge. Also the addition of one will up your flow in the display due to the return pump.
If you search sumps here you will find a ton of info on how to build them etc.

[Narmical]

so you hang the filter off the sump tank rather than the main tank?

there is alot of info on how to make one.

Im new to all this (i dont even have a setup yet) and im trying to figure out what i need / dont need and what all these items do.
its all very confusing there is just SOO many things that may or may not work.

[leebca]

What you're asking about is 'systems.' There are as many different systems as there are old-time marine aquarists! They all can work to varying degrees of success. None are 'wrong' or 'right.'

To go through the virtues and faults of the various configurations is not something easily done. You should get a book that specifically takes you through different systems. Some books are suggested here: Marine Aquarium Books & Reading

A sump is a place to put equipment for the aquarium, without putting in or on the display aquarium itself. Inside the sump there are pieces of equipment like a skimmer, heater, etc. The sump can act like the display tank and you can filter (mechanical) the water there as you would the tank. It is like Samper has posted. Another value of the sump is to have an overflow, removing surface water from the aquarium thereby keeping the surface moving and available for maximum gas exchange, as well as removing any wastes that float or might stratify in the aquarium.

[Reefland]

This should really help you out:
http://www.reefland.com/rho/2006/05/overflows_sumps.php

[Narmical]

Yeah that was the first thing i read!

It still leaves me confused. That article basically explains how to set one up.

Is all that a sump does is add an extra space to the system with which you can do whatever (like filter skim etc)?

[Reefland]

Yes, it adds extra water volume (which is good) and gives you a place to add more equipment to your system without impacting the appearance of the display tank. More powerful skimmers, chillers, refugiums, etc.

[Narmical]

could you forgo having a specific hang on mechanical filter if you had some sort of filter floss in the sump that the water had to run through?

[Poseidon]

I don't use any type of floss at all usually... In a saltwater tank with live rock, and a protein skimmer there really is no need for a traditional "Mechanical filter".

[Narmical]

realy? why is that? i thought i was needed always. are there some situations where it is needed?

what about the chemical filtration? like activated carbon? is that needed? or can you stick that in the sump too?

[leebca]

In my system, the return water (coming from the tank) goes through a filter bag, before it drops into the sump. That's the only mechanical filtration I do.

[Narmical]

hmm... a mechanical filter bag seems like it would be much cheaper to replace than a commercial aquarium filter insert.

is that true?

[Reefland]

Yes. You do not need a "mechanical" powered filter.

[CSeaSee]

There are lots of tanks with no specific mechanical filtration at all and run just fine, as another point of view for you to consider.