Many things could results in ...

Many things could results in Rapid gravity filter blockage but most all mud balls formation leading to decline in the efficiency of the filter. With such a problem, you will not only backwash several times a day but often it will over flow and if the plant is located in temperate region might lead to mud balls formation further deteriorating the filter. What causes this phenomenon is mostly the efficacy of the coagulation and flocculation process. First you need to make sure you find the optimum dose of your coagulant also within that you have to make sure the flocculation is taking place within the available settlement time. Often times we tend to forget there are two forces acting on the flocs; Vander walls forces of attraction and Electrostatic repulsive forces and until these two are in equilibrium the charges will repel thereby resulting in suspended flocs that will later be carried forward to the filter and that carried over flocs is the genesis of your filter blockages, mud balls formation, backwash and a resultant turbidity greater than 5.0 NTU.