How to Observe

  1. Create a circle (about 1.5 inches in diameter). Roll up and tape a piece of paper to create a 1.5 inch diameter tube OR use your hand and create a circle by touching the tips of your index finger and thumb together.

  2. Look through this circle and compare what you see to the density scale (click button below). The scale also included in the observation form. Click on the number that best represents what you see.


  • Begin making observation in early June and continue through the end of September. Cyanobacteria blooms do occur into early Fall.

  • Observe often because blooms can develop quickly and disappear within days. We recommend counting once per week.

  • Include all the cyanobacteria you see in your circle (if individual colonies are visible) down into the water as well as those on the surface.

  • Record your observation even if you do not see any cyanobacteria. No cyanobaceria in your area is valuable information so please take the time to record the zero!

Contact us if have any questions.