With the present invention, there is provided a tracking system for tracking the amount of fluid inside a cylinder (T), and a method of operation for said tracking system. Said tracking system comprises at least one weighing element (S); at least one GSM connection module; and at least one processor. The method of operation for the tracking system comprises the steps of matching said GSM connection module with the portable device; transmitting information about the cylinder (T) placed on the weighing element (S) to the GSM connection module via the portable device; sensing, by the weighing element (S), of weight of the cylinder (T) placed on the weighing element (S); calculating, by the processor, the amount of fluid inside the cylinder (T) by using the information about the cylinder transmitted to the GSM connection module and information of weight sensed by the weighing element (S); sending a warning to the portable device via GSM connection module if the amount of fluid inside the cylinder (T) is below the threshold value.