Abstract: An improved standing valve which regulates the amount of accumulated fluid in the tubing string of an oil and gas well, to an amount that is within the purging capability of the gas-lift method. The present invention provides a hydrostatic standing valve with a floating valve seat which is displaced in response to the weight of an accumulated fluid head. A ball seals against the floating valve seat and floats with it, but the displacement of the ball is limited by a positive stop provided by a rod supported by the standing valve body. When the valve seat displaces beyond that of the ball, as limited by the positive stop, the ball is sealingly disengaged from the valve seat and fluid flows out of the tubing string.