Your example doesn't make much sense because you have confused weight with hydrostatic pressure. Think about it, one is measured in pounds, the other in pounds per square in. They are not the same thing.
The pressure gradient for fresh water is .433 psi per foot. A 100 ft by 100 ft by 100 ft cube of water weights a lot more than a 1 foot by 1 foot by 100 ft column of water. The hydrostatic pressure is the same at the bottom, 100 ft of height X .433 psi/ft= 43.3 psi.
When doing physics problems always put in the units and then cancel them as you would do in basic algebra. If the resulting units don't match what your answer should be in, you did something wrong.
For example if you are looking for a velocity the answer must be in feet /sec, mph or something like that. If your answer is in feet, or seconds or hours or feet /sec/.sec.....you screwed up.
Weight is measured in pounds.....pressure in psi.
Got it?
Edited by petrophysics1, : typo
Edited by petrophysics1, : No reason given.