Kentucky State University
A Comparison of Potential Chemical Treatments for Reducing pH Levels in Freshwater Prawn Production Ponds
Institution
Kentucky State University
Faculty Advisor/ Mentor
James Tidwell
Abstract
Commercial producers of freshwater prawns have experienced significant problems with high pH levels in the growout ponds. This is especially true in new ponds where pH levels may exceed 10 and result in significant or even complete prawn mortality. Different chemical approaches have been proposed to lower potentially lethal pH levels. Alum can reduce carbonates, gypsum adds calcium, baking soda adds carbonates, and sugar breaks down to carbonic acid, all of which could potentially reduce pH levels. However, these approaches have not been scientifically evaluated. Alum, gypsum, baking soda, and sugar were each evaluated for their ability to control pH at treatment concentrations of 5 and 10 mg/l. There were four replicates of each treatment and control (0 mg/l) using 36 380-l tanks. All tanks were filled from a single reservoir tank that had been fertilized to promote phytoplankton growth that in turn increased pH to near 10. Treatment compounds and concentrations were added at 1600 h and pH was checked each day at 1600 h over a three day period. pH values were then regressed over time and slopes of the regression lines were compared. Statistical evaluation determined slopes from experimental ponds were not significantly different (P>0.05) from those of untreated controls. Future research should evaluate higher concentrations of these chemicals for reduction of pH in prawn ponds.
A Comparison of Potential Chemical Treatments for Reducing pH Levels in Freshwater Prawn Production Ponds
Commercial producers of freshwater prawns have experienced significant problems with high pH levels in the growout ponds. This is especially true in new ponds where pH levels may exceed 10 and result in significant or even complete prawn mortality. Different chemical approaches have been proposed to lower potentially lethal pH levels. Alum can reduce carbonates, gypsum adds calcium, baking soda adds carbonates, and sugar breaks down to carbonic acid, all of which could potentially reduce pH levels. However, these approaches have not been scientifically evaluated. Alum, gypsum, baking soda, and sugar were each evaluated for their ability to control pH at treatment concentrations of 5 and 10 mg/l. There were four replicates of each treatment and control (0 mg/l) using 36 380-l tanks. All tanks were filled from a single reservoir tank that had been fertilized to promote phytoplankton growth that in turn increased pH to near 10. Treatment compounds and concentrations were added at 1600 h and pH was checked each day at 1600 h over a three day period. pH values were then regressed over time and slopes of the regression lines were compared. Statistical evaluation determined slopes from experimental ponds were not significantly different (P>0.05) from those of untreated controls. Future research should evaluate higher concentrations of these chemicals for reduction of pH in prawn ponds.