depends on the size of the tank and the bucket.
I have a 2 gallon bucket that i can pour with only one hand. i use my other had to 'catch' the water before it hits the surface. it deflects the water enough. If you have a slightly wider tank you can actually fit some buckets in the tank and then you dont have to pour so slowly. But the easiest thing to do is put a large plate in the tank and then aim for it. Besides that, get a python.
you can also use a bucket and then put a powerhead in it. and attached to the powerhead is a length of tubing aimed to the tank. Plug her in and your bucket should be empty in no time.