The septic tank is 71 inches from the bottom to the top edge of the lip that is flush with the ground. The outlet of the pump is 4.75 inches from the base of the pump. The following diagram shows the needed stand pipe if the pump was on the floor of the tank.

I bought an irrigation controller housing which is fiberglass for use under the pump to keep it off the ground. The housing is 10 5/8 inches high and 9.5 inches in diameter. This means the standpipe now needs to be 66 1/4 - 10 5/8 = 55 5/8 inches tall.