computing well volume for sanitation?

Factual Questions
1

Hello,

I need to sanitize our well but the instructions are for a 6" casing and our well has a 24" casing.

So, if a 6" well casing holds 1.47 gallons of water, how many gallons of water does a 24" well casing hold?

(I just KNOW that the figure I came up with is WRONG so I’m turning to the math minds here. Wouldn’t want to poison us by using too much calcium hypochlorite!)

Thanks!

2

Volume of a cylinder = ∏r^2 * H

Assuming H (height) is a constant, a 6" (diameter) casing holds 3.14 (3*3) = 28.26H units and a 24" casing holds 3.14 (12 * 12) = 452H, so 16 times as much water.

ETA, 23.52 gallons