Pond Stratification

Posted by on Mar 15, 2017 in Blog

Thermal Pond Stratification

High-Speed, High-Impact Change

The water in your pond naturally seeks thermal equilibrium via stratification. Stratification is seasonal. And, is responsive to changes in temperature and sudden, severe weather events such as thunderstorms. A rapid change in the pond stratification can result in a range of adverse outcomes including algae blooms, fish kills and excessive bottom weed growth.

What does Stratification look like?

During summer, warmer water is on the surface, beneath it is the thermocline layer and below that, cooler water towards the bottom of your pond.

Organic material collects on the bottom in a muck layer.

The cool bottom often has low or no oxygen (called anaerobic) with high nutrient levels. Methane, hydrogen sulfide and ammonia are released as the muck decomposes in the absence of oxygen.

A mixing of these layers, or turnover, occurs every spring and fall. Rapid turnover can cause a spike in surface nutrients, the release of toxic gasses and a sudden drop in surface oxygen levels potentially resulting in heavy algae blooms and fish kills.

Will turnover happen in my pond?

Turnover is more likely in smaller bodies of water including ponds, small lakes, stormwater ponds and lagoons. This is due to the smaller volume of water responding at a higher rate of change than a larger, more thermally stable body of water. However, this smaller volume of water is also easier to impact and maintain with mechanical and biological interventions.


Since controlling the weather is not an option, managing your pond stratification requires a mix of approaches to mitigate sudden shifts, reducing the chance of severe algae blooms and fish kills. Water management options include aeration and bioaugmentation. For ponds that have experienced a full turnover, more robust approaches may be required.

How to get started on a solution

Contact Algae Control Canada today!

Contact Smoky Trout


  • algae blooms
  • bad odours
  • fish kills
  • high pH and TSS levels
  • summer turnovers
  • excessive weeds


  • Private lakes & ponds
  • industrial wastewater treatment
  • storm water ponds
  • tailing ponds
  • industrial & agriculture