[ansel12]

I don't know where you picked all that up but toilets empty the tank when they are flushed, you adjust the ballcock to set the water level and the height of the flush valve tube determines how high the water level can be.

This is by far the most common toilet tank type.

[ansel12]

A better example of the most common toilet tank, when that handle is pressed the flapper comes up and slowly settles as the entire tank empties