The present invention provides a turbine sub-runner that is positioned to be within the vortex zone of a turbine main runner. The sub-runner includes at least two sub-runner blades, configured to monitor the relative flow of the vortex created by the main runner. A sub-runner hub will be positioned downstream of the main runner blades. A sub-runner shaft, having a threaded section, will also be a part of the sub-runner, and will be connected to the sub-runner hub housing adjustable sub-runner blades and the mechanism enabling to regulate angular position of sub-runner blades. A main runner blades control mechanism will be connected to the sub-runner shaft via threaded interface, and is capable of transferring the rotational energy of the sub-runner into angular movement of the main runner blades. As the sub-runner interacts with the changing conditions of the main runner vortex, it will act to automatically regulate, adjust, and control the angle of the main runner blades to optimize the performance of the turbine. The sub-runner uses the energy of the sub-runner blades to perform the monitoring, regulation, adjustment and control of the main runner through regulating angular position of main runner blades.