Pretreatment of seawater using the Bio-coagulation-flocculation process become an increasingly important to reduce suspended solids responsible of membrane clogging. The most minor issue that could affect production costs and shorten the membranes’ lifespan in desalination plants is the formation of cakes on the membrane layer. In this context, the study aims to constructing, evaluating, and forecasting the performance of Bio-Coagulant-Flocculants, including figuring out the ideal operating parameters of water hardness (WH) and suspended solids (TSS), the removal effectiveness of the process was increased in this context. The efficacy of these new products was assessed using jar tests and by applying the response surface methodology (RSM) and the Box-Behnken design (BBD). Three factors were examined: the dose of coagulant (chitosan), the dose of flocculant (cactus gel) and the pH of the solution, focusing on their impact on the rate of turbidity reduction. Under optimal conditions, with a coagulant dose of 0.2161 mg/L, a flocculant dose of 0.2 ml/L and a pH of 7, significant turbidity elimination was achieved (91,53%), as well as a reduction in hardness (14.64%) and TSS (79.134%). These results demonstrate the remarkable effectiveness of these bio-compounds, which could potentially replace the ineffective coagulants and chemical additives currently used in seawater desalination plants.