The misinformation on this website is pretty amazing. Most likely that is a blue-green algae. Is it floating in the middle like in little black mats?? I had some bloom here in central Indiana. Might want to find out what it is before dumping a bunch of chemicals in the lake, also the water is very cold right now and many chemicals wont work below 60 degrees. Later.
What mis-information? Blue-green algae does not "mat"...Blackened "mats" are common FA species that have floated up from the bottom and the black color is dead FA on the tops of the "mats". Also, Blue-green algae does not start it's growth on the pond's bottom.
I do agree on knowing what species you are dealing with before throwing out blanket doses of Copper products....Contact Bill Cody here and he can identify both the species and best treatments...
