Hal also has a degree in chemical engineering from the University of Florida. He has agreed to share a bit of his knowledge on the chemical and biological aspects of a recirculating system. If you are involved in operating a recirculating system, or anticipating constructing one, I don't anticipate that I could provide a better speaker or format. Total Alkalinity and Liming Total alkalinity is a measure of the total dissolved bases in water. One of the most important groups of bases which will register on a total alkalinity test are the carbonates.
Carbonates serve as a buffer for pH in water.
In a pond with low carbonate levels, carbon dioxide can cause rapid changes in the pH. During the day, carbon dioxide levels in ponds are typically low, or non- existent. Algae in the water use carbon dioxide as quickly as it is produced in the process of photosynthesis. In cases with extremely low carbonates, daily fluctuations in pH levels can be severe, causing other problems in the water quality of the pond. Limestone is calcium carbonate, and dolomite is a mixture of calcium and magnesium carbonates. By adding crushed limestone or dolomite to a pond, you can increase the carbonate and total alkalinity of a pond.