[douglas1011]

this may seem like a silly question and unfortunately i cant elaborate too much on the project but i would like to know how much brine would be needed to diffuse along a sea water pipe so that the pipe water became brine.

Once the brine has diffused fully into the pipe it will be thrown away and a new container of brine will be connected to the pipe.

i am looking for an equation that would help me find the answer through a range of volumes.  From large containers of brine diffusing into small pipes to small containers of brine diffusing into larger pipes.