The GAS filter achieves significant softness by balancing the anti-spring effect by horizontal compressive force and intrinsic vertical stiffness of the cantilever blade. Due to the softness, the vertical position of the keystone moves easily in response to a small change of the payload mass and the blade springs’ physical properties. The thermal drift due to the temperature dependence of the Young’s modulus of the spring material is an especially big issue in operating the GAS filter. If the GAS filter is balanced at the working point with a payload mass of M, the optimal load to keep the keystone at the working point is shifted with the temperature change by: