Considering fertilization and ponds with green water, you should be most concerned when the surface as thin green or blueish green films on the surface that distribute and move with wind. Most all the cyanotoxin producing algae form surface films. However not all green surface films are caused by Cyanobacteria and sometimes a specie will form toxins and sometimes not. Current consensus is toxin production has to do with the amount of nitrate nitrogen in the water. To complicate things, there are a few genera of toxin producing Cyanobacteria (bluegreens) that are truly planktonic and thrive in the water column and do not form surface films. However not all green surface films are caused by Cyanobacteria. The general rule is to be cautious when green surface films are present.
Last edited by Bill Cody; 06/26/19 02:01 PM.
