Eco-friendly pH monitoring in aquaculture: A comparative study of biomass waste extracts with different setup designs.

Maintaining optimal water quality is critical for the success of aquaculture operations, where pH monitoring plays a pivotal role. This study presents a novel approach for pH monitoring in aquaculture ponds by harnessing biomass-based indicators and smartphone-based colorimetric sensing using different setups designs. Three biomass indicators including red cabbage, mango leaf, and used coffee grounds extracts were tested. Standard solutions across a pH range of 1-13 were tested using four setups: black and white polypropylene enclosures, a polyethylene pipe assembly, and a polystyrene tray configuration. The polystyrene tray configuration was determined to be the most effective, as its longer light path (4.5 cm) significantly enhanced color visibility and produced more vibrant color changes, making it ideal for further investigations. The method is as follows:•Water samples were collected from aquaculture ponds. pH were analyzed using this method and standard pH meters.•Mango leaf extract showed strong pH sensitivity and correlation (R² =0.9654).•The mango leaf extract attained a quantification accuracy of 0.5 pH units within a pH range of 3-12.•This smartphone-based approach offers simplicity and ease of implementation empowering aquaculture farmers with a practical tool for monitoring water quality.