It is an old strip mine, but I dont think acid seepage is the problem. The bottom is very dark rich sediment and the water doesnt get much wind action from being tucked back into the trees.
The algae is a cold water algae that is blooming up on the surface now, but will retreat to or below the thermocline for the summer. I have spent a few hours today researching what can be done.
Basically the algae could release its toxins at anytime, but especially when it dies. (shouldnt treat it with algaecide) BUT It is so thick at the surface that it is blocking the sunlight from the rest of the water. So there is a good chance the fish are going to die soon no matter what I do? Installing an aeration system this time of year could create open water and allow sunlight to penetrate better, but that comes with another set of risks for the fish.
