similar sort of way, you just put it in the path of the water.. and it'll remove chemicals.
For clearing the water, it depends on why the color.. if it's particles in the water, finer filter media would help more,. if it's bacteria, then time is normally best, if algae lowering the light level of photo period would work.
If you want to use carbon, it won't hurt anything, unless you are adding chemicals for some reason... Just add it and see what happens, remember that it won't be useful after about a week, maybe 2.
It will be useful regardless of the time before it is chemically expended as a BB media. Purigen is a great option, but IME it doesn't remove discoloration or odors as quickly (if you have those issues) as pure activated carbon does.