The following material has been taken from a sheet entitled Several Faulty Assumptions Are Used in all Radiometric Dating Methods.
We say that the input and output of water is in equilibrium.The water level just sits there even though the hose is going full blast.To that end, he quoted some authorities, including Richard Lingenfelter.Having accomplished that, Morris concluded that the barrel was still in the process of being filled up and that, given the present rate of water coming in and leaking out, the filling process began only 10,000 years ago.(The barrel is made deep enough so that we don't have to worry about water overflowing the rim.) Henry Morris argued that if we started filling up our empty barrel it would take 30,000 years to reach the equilibrium point.
Thus, he concluded, if our Earth were older than 30,000 years the incoming water should just equal the water leaking out.
Now, the fuller that barrel gets the more water is going to leak out the thoroughly perforated sides, just as more carbon-14 will decay if you have more of it around.
Finally, when the water reaches a certain level in the barrel, the amount of water going into the barrel is equal to the amount leaking out the perforated sides.
We stick the garden hose in and turn it on full blast.
The water coming out of the hose is analogous to the continuous production of carbon-14 atoms in the upper atmosphere.
That is, the equilibrium point should have long since been reached given the present rate of carbon-14 production and the old age of the earth.