Ok why would u need a filter AND a protien skimmer?
Aren't they practically the same thing except skimmers work better?

I read on this site on the equipment list for an octopus that skimmers filter waste and other chemicals before the filter even has to worry about it.
So when I get my octo, should I get BOTH a filter and a Skimmer, OR just a Skimmer?
Weird.

not weird!

The filter is the life support machine in the tank and breaks down chemicals in the water into less harmfull ones.

The skimmer removes a lot of the waste before the filter has to break down the materials... BUT the skimmer also creates huge amounts of Oxygen in the water and in an emergency like an octopus inking, is the only sure fire way of removing all the ink.

Some reef tanks can be set up with live rock and a skimmer and that's it... for a messy octopus though i dont think it would work in anything smaller than 200gals and a 4 foot tall skimmer!

ThanX.

So I should totally get both becuase it will work together effectively right?

yep, that's it! :)

Just an added note...technically, the filter can remove fine and coarse material that the skimmer mostly doesn't, too. Mine does filter such stuff, though I don't know how much a contribution this is.

rusty