ABSTRACT
The dissolution rates of gypsum blocks measured as weight loss after an
exposure time of a few hours or a few days can be used as an index of
water movement in aquaculture ponds. Weight loss from gypsum blocks
increased linearly with increasing velocity of water flowing over the
blocks. Weight loss was constant for an exposure time of at least 9 or 10
days. Rate of weight loss decreased with decreasing temperature and with
increasing salinity. However, for conditions existing for freshwater and
brackishwater ponds, the weight loss over an exposure period of 8-24 h
can be easily measured. A method for preparing the gypsum blocks is
presented and an example of their use is provided.