1. A cooling tower monitoring system comprising: a cooling tower system; and a computing device that is communicatively coupled to the cooling tower system, the computing system comprising: a memory comprising computer instructions; and a processor coupled to the memory, wherein, when executing the computer instructions, the processor effectuates operations comprising: receiving at least one measurement of a composition of a fluid used in the cooling tower system, the at least one measurement from a cooling tower sensor of the cooling tower system; generating a predicted output of a cooling tower system based on a model of the cooling tower system; generating an estimated output using an extended Kalman filter with the at least one measurement and the predicted output as inputs, wherein the estimated output represents a characteristic of the fluid used in the cooling tower system; determining a bias in the at least one measurement from the cooling tower sensor based on the estimated output and the at least one measurement; adjusting the at least one measurement from the cooling tower sensor to correct the bias; and adjusting the composition of the fluid used in the cooling tower system based on the adjusted at least one measurement.