Use of agricultural limestone and lime in aquaculture.

Abstract

Application of agricultural limestone to increase alkalinity to about 50 mg/l improves production in fertilized ponds and enhances water quality in ponds for feed-based aquaculture. Burnt lime and hydrated lime cause an initial high pH, but they can be applied to bottoms of empty ponds for the purpose of neutralizing bottom soil acidity. In addition, even where acidic soil and low alkalinity are not present, burnt or hydrated lime also may be used to raise pH and disinfect pond bottoms. In ponds with low dissolved oxygen and high carbon dioxide (CO₂) concentrations, burnt lime at 1.28 and hydrated lime at 1.68 times CO₂ concentration will remove CO₂ and prevent it from interfering with oxygen uptake by aquatic animals. Small, frequent applications of lime sometimes are made to ponds to remove CO₂ and phosphate, limit phytoplankton growth, and stabilize pH. The effectiveness of this practice is dubious.