I have one of these but I can never get it to stay in the bucket for long. I end up with water on my carpetfluttermoth said:You need a 'gravel cleaner'; like this;
You put the wide end in the tank. Then you start a syphon; either by sucking on the end of the tube, or by immersing the whole thing in the tank until it's full of water and put the end of the narrow pipe in a bucket you have on the floor.
There are loads of 'how to' videos on YouTube