Why is the pH of my pond so much higher in the afternoon?

The pH of a pond containing algae will increase during the day because algae remove carbon dioxide from the water during photosynthesis in the presence of sunlight. Carbon dioxide (CO2) is acidic in water. Algae and microbes tend to drop pH in the pond during the night as they algae respire and add CO2 back into the water.

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Pond issues and management

Ken Wagner, Ph.D. from Water Resources Services discusses the problems observed in ponds, the causes of algae problems and the alternative to manage water quality in ponds.


 

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