If you have a really dense planted tank, IMHO, you really only need mechanical filtration, and the plants will take care of the rest.
I run two cannisters on my 90, and one is STUFFED with pillow fluff from wallyworld, and the other has sintered glass - only because it was expensive, and I don't want to throw it out. But if it fell to the floor, I would replace it with pillow fluff also.
I was a fool, and let the one canister go *way* to long (over a year!) between cleaning, and when I got around to it, the fluff was so full of slime and crap, it felt like pudding. But it certainly did it's job.
90 Gallon, eco, pressurized, controlled, 240 watts.