The important water quality parameters are not the lethal levels or LC 50 but the lower levels which prevent optimal growth. Table bellow contains the recommended levels and maximum fluctuations for optimal growth. Many systems for monitoring water quality have been suggested, some of which are impractical under commercial conditions. The minimum number of parameters that should be monitored routinely are pH, dissolved oxygen and transparency. These give some indication of the health of the plankton bloom and suitability of the water for the shrimp. Dissolved oxygen and pH should be measured twice a day, first between 3.00 to4.00 pm. Both measurements should be taken in the feeding area near the pond bottom, however in practice, pH is often measured approximately 0.5 m. below the surface. The samples should be tested at the pond side and not transported to the laboratory. The transparency of Secchi discreading should be measured in the afternoon at the same time as the dissolved oxygen and pH. The area selected for measuring transparency should be representative of the pond and not in areas with very high or low levels of plankton due to wind action or water exchange. Although the regime described here may be adequate for routine operation, if problem occurs it is preferable to measure as many parameters as possible to obtain the maximum information on which to base decisions.