Generally, all industry processes are nonlinear which require parameter control to the achieve desired performance. Nonlinear systems do not satisfy the superposition principle or their output is not directly proportional to its input. Process industries employ spherical tanks for their storage capacity. Controlling the liquid levels in spherical tanks is one of the difficult problems in process industries. Due to its dynamic behaviour and tank cross-section area, the real-time model of the Single Spherical Tank Liquid Level System (SSTLLS) includes nonlinear properties and is expressed as a Single Input Single Output (SISO) model using a simple first-order equation. However, practically the SISO model derived will be a First Order Plus Dead Time (FOPDT), which requires a good effective controller to maintain the steady-state level of the tank. However, the PID controller is the most widely used because of its simple design and easy tuning process and it becomes a challenge to control the liquid level in a spherical tank system due to its nonlinearity. In this research, the level of the spherical tank is controlled using Fractional-Order controllers. Here the use of the Fractional-Order PI (FOPI) and Fractional-Order PID (FOPID) controller is designed based on the Approximate Generalized Time Moments (AGTM) tuning method for the nonlinear SSTLLS to study their response with that of the reference model. The main objective is to get the closed-loop response near the reference model which is very much feasible. Performance indices such as Integral Squared Error (ISE) and Integral Absolute Error (IAE) and time domain specifications including Rise time, Settling time, and Peak time with traditional PI and PID controllers with different tuning techniques are compared with the performances of Fractional-Order controllers and is implemented in the MATLAB environment.