Membrane technology has played a vital role in the treatment of water and wastewater in Singapore. Fouling is a commonly encountered problem that can dramatically diminish the treatment process efficiency and cost effectiveness of membrane related treatment. Traditionally, flux or TMP change were used to determine the timing and frequency for cleaning foulant. However, our preliminary results had showed these two parameters may mislead the cleaning programme settings. Thickness and strength, which are two direct properties of the foulant, provide more representative and complementary information for optimization of operating protocols, cleaning regimes and module design. The fluid dynamic gauging (FDG) is able to provide additional valuable information which is the foulant strength. In addition, FDG is also able to uncover the removal behaviour of biofilm through local biofilm strength. Our findings suggest that FDG is able to provide valuable additional information related to biofilm property that has not been disclosed by other monitoring methods.