A method of treating a subterranean formation penetrated by a wellbore is accomplished by introducing a fluid into the wellbore containing a combined fluid loss additive and breaker. The pressure sensor may be a continuously variable output device such as an analog sensor, pulse width modulation sensor, a similar device or, less desirably, a two state sensor. To control data stream congestions in the channel and maintain the visual display quality above a certain level, the present invention exploits the human visual perception and adaptability to changing visual conditions.