Have you ever tried picking up a rock when it is underwater, and it feels light? But then when you take it out of the water, it is super heavy? That is how the link you posted works. Whoever invented it made a regular counterweight and put it inside a tube. When he wants the counterweight to get lighter, he pumps in some water.
It isn't a bad idea, but much more expensive and difficult to make than my idea. Plus, I don't like the idea of steel cables being constantly wet for years and years, rusting, and deciding to snap when I am on the 6th floor.
My idea is simple and different - imagine a seesaw with a kid on one side, and a big empty tank of water on the other side. If you want to lift the kid up, you put in exactly his weight of water, and then one cupful extra. When you want the kid to go down, you take out the cupful you put in to make him go up, plus take out one extra cupful to make the kid heavier than the tank of water.
elevators are just seesaws with pulleys. And a motor to unbalance them of course.