Diesel treatment does not "get rid " of the water. Diesel treatment such as Grotamar 71 treats the algae that grows on the water diesel boundry layer which is important.
You need to take out almost all of the water through either a tank drain, or the primary filter ot the engine mounted fuel filter. Water going through your fuel pump is mucho expensivo dont even think about it.
Find the source of your water in the fuel tank, cure it , remove any water you can and inspect filter regularly and trat your fuel with a algaecide.