I'm kind of confused on the value to determine pressure. I'm told that 2.31 feet equals 1 psi of pressure. But the formula F/A force divided by area brings up a different number. So I've got 6 feet hight of water with a 1 inch diamter area. So what I did is use LxWxH/1728 x 10 to get value in gallons (imperial gallons) and multiplied by 10.0200098 pounds to get the weight. Then divided by .785398163 square inches. So 4.175004083lbs / .785398163 = 5.315780301 psi. But according to the value above is 2.31 feet to 1 psi is 2.594402597 psi for 6 feet. What is wrong here?