Method of operating a submersible agitator, comprising the following steps; 1) providing a submersible agitator for accelerating a suspension, comprising at least one actuator module , at least one fluid accelerator module , a transmission module which transmits the generated kinetic energy to the fluid accelerator module along the same or different axes and gearbox modules which allow adjusting the rotation speed gradually, wherein - at least one of the actuator module , the transmission module and the fluid accelerator module is independent from the others, - the actuator module , the gearbox modules , the transmission module and the fluid accelerator module comprise an actuator module connection surface , gearbox module connection surfaces , a transmission module connection surface and a fluid accelerator connection surface respectively, which match at least one of the respective connection surfaces, in order to allow connection between at least any two of the actuator module , the gearbox modules , the transmission module and the fluid accelerator module ; 2) selecting an operation without the gearbox module , with one gearbox module or gearbox modules connected in series, depending on the requirements in order to meet the user requirements for different media; 3) operating the submersible agitator according to the selection without the gearbox module , with one gearbox module or gearbox modules connected in series, allowing establishing different propeller rotation rates depending on the number of gearboxes. 1) providing a submersible agitator for accelerating a suspension, comprising at least one actuator module , at least one fluid accelerator module , a transmission module which transmits the generated kinetic energy to the fluid accelerator module along the same or different axes and gearbox modules which allow adjusting the rotation speed gradually, wherein - at least one of the actuator module , the transmission module and the fluid accelerator module is independent from the others, - the actuator module , the gearbox modules , the transmission module and the fluid accelerator module comprise an actuator module connection surface , gearbox module connection surfaces , a transmission module connection surface and a fluid accelerator connection surface respectively, which match at least one of the respective connection surfaces, in order to allow connection between at least any two of the actuator module , the gearbox modules , the transmission module and the fluid accelerator module ; - at least one of the actuator module , the transmission module and the fluid accelerator module is independent from the others, - the actuator module , the gearbox modules , the transmission module and the fluid accelerator module comprise an actuator module connection surface , gearbox module connection surfaces , a transmission module connection surface and a fluid accelerator connection surface respectively, which match at least one of the respective connection surfaces, in order to allow connection between at least any two of the actuator module , the gearbox modules , the transmission module and the fluid accelerator module ; 2) selecting an operation without the gearbox module , with one gearbox module or gearbox modules connected in series, depending on the requirements in order to meet the user requirements for different media; 3) operating the submersible agitator according to the selection without the gearbox module , with one gearbox module or gearbox modules connected in series, allowing establishing different propeller rotation rates depending on the number of gearboxes. <EOS>