I have data of water quality and production parameter of shrimp culture. The water quality parameter including weekly pH, salinity, NO2-N, and TAN; where production including harvest weight, shrimp size and feed conversion ratio (FCR). I have analyzed the correlation (Pearson) between them, and seemed there was no parameter that significantly correlated. Colleagues said that it might be the water quality fluctuation that affected the harvest weight, shrimp size and FCR. Does it seem make sense? I need suggestion how to measure the fluctuations in water quality between weeks of observation (data transformation etc.).