In determining the amount of copper sulfate needed for pond treatment, the alkalinity and acre-feet of water must be found. The average weight needed is 2.75 pounds per acre-foot of water.
The alkalinity is given in parts per million from a test kit, then divided by 100. That result is the concentration of copper sulfate in ppm. The number of acre-feet can be calculated by finding the surface area and multiplying by the average depth, with the factor of one acre-foot equal to 43,560 square feet of one-foot deep water. The University of Florida IFAS Extension does not recommend the use of copper sulfate in certain situations, so it's best to check.