Calcium carbonate scale is a problem in many industrial and domestic processes, as it precipitates from solution to form a hard deposit which grows on equipment surfaces. The potential for scale formation and aggregation is present whenever a solution becomes supersaturated. Scale formation and prevention creates a considerable capital, operation and maintenance problem. Achieving effective and economical scale control and removal is consequently a major concern for efficient and safe industrial operations. To prevent such potential problems, it is important to understand the mechanism of the calcium carbonate scaling process. This paper is part of the continued effort to understand calcium carbonate formation and mitigation related to oilfield operations. The paper describes the application of a new method, based on laser refraction measurement in transferring the signals to current, to determine the formation of calcium carbonate scale in high calcium brines. This method provides a real-time measurement of the magnitude of scaling crystals, and has been proven to be a sensitive method to monitor the initial stages of the precipitation process. This study focuses on the comparison between two techniques to evaluate formation and aggregation of scale in the presence and absence of scale inhibitors at different temperatures. Also, the efficiency of laser technique will be assessed as an effective tool for the scale and aggregation inhibitors performance and ranking, where the results will be compared with the offline measurement technique using a static test method. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.