sump what is it for

[ariel8675]

for a 90 gallon tank is a sump essential or just a good thing to have, and whats the exact purpose. Can I make this.

[theatrus]

Its a good idea.

Main perks:
Gives you more water volume
Perfect place to hide pumps and equipment, and most larger skimmers need to be placed in a sump.
You can partition it and create a refuge section.

The easiest way to make a sump is to simply buy a rubbermaid bin or a second smaller aquarium. The aquarium is easy to section off by siliconing in self-cut acrylic baffles.

If you need some ideas on sumps, check this out: http://www.melevsreef.com/allmysumps.html

[Angel*Fish]

Can include a refugium area and /or area to grow algae for nutrient export

Can make water changes easier - I empty my 30g refugium when changing the water as opposed to removing from it the main tank - that way the water level always stays up and the fish aren't "freaked out"

My kalk dosing is done in the sump, also water top offs - so it's signifcantly diluted by the time it gets up to the main tank

[Shagsbeard]

Evaportation causes the volume of water in your tank to drop. If you have a sump, the level of water drops in the return portion of your sump rather than your main tank. You will never see the level of water change in your tank unless something is going wrong with your plumbing or return pump.